The Classroom Aquarium

Pets are a common fixture in many elementary classrooms all around the country. I still remember walking into my 2^nd grade teacher’s room and brimming with joy that she had a fish tank. And I’m not alone in that delight. Many researchers have found that classroom pets have a positive impact on students. Pets increase students’ positive attitude towards school and can actually make them want to come to school (Anderson & Olsen). They have been found to improve the emotional well-being of students and contribute to humane education (Daly & Suggs). Contrary to popular belief, one study showed pets did not distract from the teacher (Kortschal & Ortbauer).  And of all the possible choices for classroom pets, fish are the most common (Rud & Beck).

Freshwater aquarium (Neale Monks)

This is with good reason. Fish are relatively easy to care for. They don’t need to be fed daily, so they can easily be left over the weekend or a short break. During the summer, they can be taken home or just cared for on a weekly basis. There are also a wide variety of species that can be very easily acquired. It is also possible to keep fishes that are native to your location to give students a view of wildlife they don’t normally see.

Aquariums also have a well-established relaxing effect. Watching aquariums is known to reduce heart rate and blood pressure (Cracknell et al). And if I remember school correctly, tests certainly can generate some elevated heart rates! My mother is a middle school teacher and if there is one thing teachers need, it’s reduced stress levels. So in this way, the fish tank will help the teacher as much as the students. 

Lessons with an Aquarium

Aquariums can be very useful teaching tools. Students can examine how a fish tank attempts to reproduce a native habitat. How the light emulates the sun; how the filter gives the fish clean water like a stream; how the pump oxygenates the water like a waterfall. If native species are available students can observe their natural habitat and try to recreate it. Fish don’t have to be the only inhabitants in an aquarium. Plants can be added to further simulate a natural environment. Plants can also be used to introduce students to the idea of nutrient cycling.

Trout Unlimited volunteer helping with tank maintenance on the class's Trout in the Classroom project. Trout in the Classroom is a program started by the nonprofit Trout Unlimited which seeks to preserve freshwater streams and rivers around the USA. Students raise fish from eggs and release them at the end of the year. (Julia Ross, Troutfest.org)

Water chemistry and pollution are other lesson that can be taught with fish tank. Many pet stores carry small freshwater testing kits simple enough for middle school students. They can measure, record, and graph the temperature, pH, and nitrate levels in their fish tank. These water quality readings can be compared to local a river or pond. Teachers can actually let the fish tank get dirty to show students what happens to fish in polluted environments.

The nitrogen cycle is very important to success with an aquarium, and although it isn’t the same nitrogen cycle that happens in the air, it can be used to introduce students to the concept. Fish tanks can also help illustrate the water cycle from cloud to ocean. Students can even measure how much water evaporates from the tank on a weekly basis.

Math and science are very tightly linked, so an aquarium can also help with math lessons! Students can calculate the volume and surface area of the fish tank and convert those measurements from metric to standard units. From the volume, you can have them calculate the weight of the aquarium (hint hint, water weights 8.34 lb/gallon). These fun examples bring math out of the textbook and into real world.

Help Setting up a Tank

Right about now, you may be thinking, this sounds great but where do I start? Thankfully fish tanks aren’t difficult to set up and maintain, but they will require a bit of effort on your part initially. The first thing you will want to read and research is the freshwater nitrogen cycle. This is the article I wrote on it. Many many resources exist online to help you in starting a fish tank, and I encourage you to check out the other fish blogs I recommend for additional resources. My friend Mari at Aquariadise has some wonderful articles to help new fishkeepers such as types of filters & choosinga substrate. The National Science Teachers Association also has guidelines for keeping live animals in the classroom which I highly recommend reading.

Suggestions to a New Fishkeeper

If native fish are at all an option, I highly recommend them. In the eastern USA we have many stunningly beautiful fish right in our own backyard. You can read more about them in my article: The Beauty in Your Backyard.

 If native fish aren’t an option, then the next best suggestions I can make are small tetra like the glowlight (Hemigrammus erythrozonus) and X-ray tetra (Pristella maxillaris). Small barbs like cherry barbs (Puntius titteya) and gold barbs (Barbodes semifasciolatus) also make great classroom fish. Zebra danio/glo-fish (Danio rerio) are a staple and great, hardy fish. All of these species need to be in groups larger than 10 because they are shoaling species, meaning they survive best when in groups. They all need a tank larger than a 10 gallon, too. You can read more about these species in my article: Best and Worst Beginner Fish.

A few of the glowlight tetra in my personal tank. They are rather hardy and don't mind me leaving them for a weekend. 

For tank size, I recommend starting with a 20 or 30 gallon tank. It seems counter-intuitive but small tanks are actually harder to keep. Larger volumes of water mean there is more of a buffer in case something goes wrong. Larger tanks also mean you’ll be able to keep more fish which are always delightful to students.  

I highly recommend plants in an aquarium. They create a soothing natural environment and open new doors for educational opportunities in addition to helping keep it clean. To successfully grow plants you will need a plant-specific light. An aquarium kit should come with a hood and light, but that light isn’t going to be tailored to plants. You will need to get a 6500k full spectrum daylight bulb. Many pet stores also sell these, but hardware stores will have them if your pet store doesn’t. They only need to be replaced once a year to keep your plants growing green and beautiful. Some plant species that are a good, hardy beginner species are anubias, java fern, amazon sword, and duckweed. Pet stores often have these common plants for sale.

Help with Funding

Aquariums (like all pets) require money, but fortunately for you, there is a nonprofit organization that gives grants for teachers interested in getting a classroom pet. Pets in the Classroom allows teachers to submit proposals for grants to assist with setting up and maintaining classroom pets. Their website also contains lesson plan and habitat ideas for many species of pets. I highly encourage you to check it out. If regulations and demographics allow, you can ask for a small donation from your students to help fund your classroom pet experience.

Works Referenced

Anderson, K.L. and M.R. Olson. 2006. The value of a dog in a classroom of children with severe emotional disorders. Anthrozoös 19(1): 35-49.

Aquatic WILD: K-12 Curriculum & Activity Guide. 2013. Revised ed. Council for Environmental Education, Houston.

Cracknell D., M. P. White, S. Pahl, et al. 2015. Marine Biota and Psychological Well-Being: A Preliminary Examination of Dose-Response Effects in an Aquarium Setting. Environment and Behavior. DOI: 10.1177/0013916515597512

Daly, B. and S. Suggs. 2010. Teachers’ experiences with humane education and animals in the elementary classroom: implications for empathy development. Journal of Moral Education 39(1): 101-112.

Kortschal, K. and B. Ortbauer. 2003. Behavioral effects of the presence of a dog in a classroom. Anthrozoös 16 (2): 147-159.

“Responsible Use of Live Animals and Dissection in the Science Classroom.” National Teachers Science Association. www.nsta.org/. Updated: March 2008. Retrieved: 24 Nov 2015.

Rotman, E. 2008. Hatching Stewardship. Outdoor California (March-April): 33-35.

Rud, A.G. and A.M. Beck. 2003. Companion animals in Indiana elementary schools. Anthrozoos 16 (3):241-251.

Rutherford, B. 28 March 2015. Tanks in Classrooms: Setting Up an Educational Aquarium. Reef to Rainforest Media. Retrieved: 24 Nov 2015.

“Trout in the Classroom.” Trout Unlimited. www.troutintheclassroom.org/. Updated: Nov 2015. Accessed: 24 Nov 2015.

Marimo (Aegagropila linnaei) Care

Basics 

Marimo, sometimes called moss balls or marimo balls, are a popular aquatic pet. While not an animal, many people keep them as pets due to their cute nature and easy care. Marimo aren’t a plant either. They are made of a type of cladophora algae that is rolled into balls by wave action (or by hands in captivity).  This algae is very slow growing and will not spread to the rest of your aquarium. They grow approximately 5 mm (0.2 in) per year, so there is not threat of it taking over your tank.

Marimo can live for a very long time. They grow continuously and at the same rate. The largest marimo is 95 cm (37 inches) in diameter. Given their growth rate, it is over 200 years old. Most marimo in home aquaria only reach 20–30 cm (8–12 inches). You can find them sold anywhere from 5 mm (0.2 in) up to 10 cm (4 in). The larger the ball, the more expensive it will be.

Giant marimo on display at Lake Akan (bugfox.net)

In the wild, marimo are only found in lakes in higher latitudes. Colonies are known to exist in lakes in Japan, Scotland, Iceland, and Estonia. Two lakes in which they occur—Lake Mývatn in Iceland and Lake Akan in Japan—are protected by law. The colonies in Lake Akan are known to grow the largest and most rotund marimo. They live between 2 and 2.5 m (6.5 and 8 feet) deep where gentle wave action turns them over, keeping their cute ball shape.

Marimo are not the only form of Aegagropila linnaei. It will grow on the shaded side of rocks in an epilithic form or free-floating filamentous form that can form a carpet on the muddy lake floor. When small filaments of the algae get rolled into balls, they take the marimo form. These balls do not have a hard center and are algae all the way through.

Minimum tank size

Marimo necklace (SewOeno @ Etsy)

As long as the marimo is covered in water, the tank size doesn’t matter. Nano marimo (5 mm or smaller) can actually be housed in containers small enough to hang around a necklace. As the marimo grows it will need a larger container. You don’t even have to keep them in traditional aquariums with filtration as long as you change the water periodically. Water movement is also not necessary.  Decorative vases can be used as well as mason jars or anything that holds water. They can be kept in closed jars as long as you open the top every once in a while to let some fresh air in.

Temperature Range

Coming from high latitudes, marimo prefer cooler temperatures. They can handle temperatures up to about 78F (25C). Above that their growth can be affected or they can fall apart. When the water temperature begins to get this high, consider moving your marimo’s home to a cooler part of the house and change the water more frequently. Even though they come from cool lakes, marimo cannot take freezing temperatures. Protect them from frost.

Water Quality

Unlike fish whose waste products (carbon dioxide and ammonia) are harmful to their health, marimo’s waste product (oxygen) isn’t harmful. But they do need periodic water changes to replenish the minerals in the water taken from photosynthesis. It is also recommended to change the water more often in the summer to help keep the marimo cool.

When you change the water, you should remove the marimo and give it a gentle rinse in cool water. This will wash away any particles that may have attached to it. Roll it gently in your hands to help it maintain that cute ball shape. 

Marimo are unfussy when it comes to water parameters. A pH between 6 and 8 will suit them just fine. They will grow and flourish in just about all levels of water hardness. Interestingly, they can also take brackish water (to learn more about brackish aquariums read this article). In Lake Akan in Japan the filamentous form grows abundantly where salty water from natural springs flows into the lake. Sometimes a pinch of salt will help marimo recover when they have brown spots.

Food

Marimo are algae, and algae operates much the same way as plants. They get their food from the sun. The only thing you need to give your marimo is light. A simple desk lamp will do. Indirect sunlight like that from a north eastern window (in the northern hemisphere) is good. Avoid long hours of direct sunlight as marimo can get too much light.

Substrate

Any type of substrate is fine for marimo. People keep them on everything from sand to bare-bottom tanks. However, some people have found sand can get tangled in the threads of algae. I had a similar experience with my marimo and sand, and now I use large gravel or bare-bottomed tanks.

Tank Mates

Given the right-sized aquarium almost any fish makes a great companion for a marimo. Fish that eat algae like plecos, mollies, and hillstream loaches will not make good companions because their grazing on the marimo will likely outpace the marimo’s growth. The few fish that require temperatures regularly over 80F like discus will also be a poor choice for a marimo.

Goldfish

These beautiful golden fishies are often seen with marimo but not always in proper homes. Despite what seems to be everywhere, goldfish do not belong in bowls. You can read more about why they don’t belong in bowls in my goldfish care article. Even when placed in a large enough aquarium, goldfish aren’t the best companions for marimo as goldfish are known plant-muchers. They love soft plants and algae. Marimo are usually at the top of their list. Most goldfish will tear apart marimo. There is the odd case where a goldfish doesn’t eat a marimo, but why take the risk?

My marimo wrapped in twine to regain their shape after they lived in the goldfish tank.

Betta fish

Sometimes known as Siamese fighting fish, these little beauties are another common marimo companion. Like goldfish, they are often put in bowls but are not happiest there. You can read about why in my betta care article. Betta are another iffy choice for marimo as their temperature ranges only overlap a bit. Some people claim it doesn’t matter for the marimo, but others think it does. It might depend on the marimo. Some can take the warmth and others can’t. If you do choose a betta to be your marimo companion, be sure to have a backup plan in case your marimo can’t take the heat.

Good fish choices

Now that I’ve established some not so great fish choices, I’m going to give you a few species of common fish that have a better potential to work with marimo as they like the same cooler water and won’t munch on marimo. All of these fish need an aquarium larger than 10 gallons, and some will need a larger tank. For groups of fish fish look into zebra danio, neon tetra, glowlight danio, guppies, and white cloud mountain minnows. These fish are shoaling species which means they need to be around 6 or more of the same species. For a more solitary companion an axolotl is a good choice. They are actually a salamander not a fish, but they like the same low-light, cool conditions that marimo thrive in. You should research the needs of any fish you decide to keep with your marimo.

Shrimp

While shrimp eat algae, marimo are not on their dinner menu. Red cherry shrimp and ghost shrimp are two of my favorite shrimp commonly available. As their name implies red cherry shrimp are more vibrant than ghost shrimp. But red cherry shrimp will breed and may overpopulate a small tank. Ghost shrimp are much less likely to breed. They also grow larger than red cherry shrimp. Both shrimp love to graze on the bits and pieces that get trapped on a marimo and make great marimo companions.  

Red cherry shrimp cleaning a marimo (RW Sinclair on Flickr)

Snails

Another good choice for marimo are snails. These invertebrates eat algae but again marimo are not on their menu. Small snails like pond snails, ramshorn snails, and Malaysian trumpet snails do well in small tanks with marimo. Large snails like apple snails, mystery snails, and rabbit snails will need an aquarium larger than 5 gallons as well as supplemental food. Unlike the small snails, large snails can’t survive on the bits and pieces of debris around the aquarium.

Interesting Facts

Ceremonial returning of marimo to Lake Akan
(lake-akan.com)

Marimo are of great cultural importance in Japan where they have been declared a national treasure. Their name comes from the Japanese language and means “bouncy water plant.” When they were declared a natural treasure in 1921, people came from all over to collect and sell them as souvenirs. As a result the population in Lake Akan declined. It was dealt a further blow when a hydroelectric power plant was built along the Akan River which flows from the lake. The level of the lake dropped and hundreds of marimo were left stranded and dying in the exposed shoreline.

The local people recognized the treasured marimo was in trouble and launched a massive effort to protect them. An appeal went out to the people of Japan to return their marimo to the lake, and they responded in droves. The locals were so overjoyed by the effort of the people of Japan that they held a festival to celebrate the generosity of the people. The three-day annual marimo festival continues to today in Hokkaido.  One of the popular items in and around Hokkaido is an anthropomorphic version of marimo called Marimokkori. San-X also created Marimoko, a smiling plushie marimo.

Around Lake Akan there is a famous legend about the origin of marimo. It says the daughter of a chief of a powerful tribe living on the banks of a lake fell in love with a commoner, but her parents objected to the relationship. To be together, the couple gave up all of their possessions, ran away together, became marimo, and lived happily ever after. For this reason, marimo symbolize love in Japan and are often given as gifts to loved ones. It is believed that if you take good care of a marimo, it will bring you happiness and good luck.

Works referenced

"Marimo and Lake Akan." Japan Atlas. Updated: 20 Febuary 2013. Accessed: 25 October 2015.

"Marimo Balls." Aquariadise. Updated: 13 May 2013. Accessed: 25 October 2015. 

"Marimo Care." Buy Marimo. Updated: 2014. Accessed: 25 October 2015.

"What is a Marimo." Marimo Sanctuary. Updated: 20 October 2015.  Accessed: 25 October 2015.

**Disclaimer** Since there is little to no scientific research about fishkeeping published, much of the hobby today is opinion, but they are opinions given by keepers and breeders who have been doing this longer than some of us have been alive. Temperature ranges and adult sizes are not opinion. They have been scientifically documented.

The Beauty in your Backyard

North American Native Fishkeeping

The first time I saw picture of a darter was in my ichthyology class, second semester of my junior year. We’d just finished covering marine fishes of the eastern US and were starting on the freshwater fishes. I couldn’t believe my eyes. I never knew there were such beautiful fish right outside my door. The first time I saw a darter in the flesh, I was forever entranced.

Redfin darter Etheostoma whipplei I caught while in Arkansas

When most people think of North American fishes, largemouth bass (Micropterus salmoides) and channel catfish (Ictalurus punctatus) are the first things to come to mind. These large gamefish are the ones that are seen and talked about the most, so it is no wonder that is where most minds go first. But there is so much more in our waterways than just these well-known fish. Surprisingly a lot of these are pretty easy to keep in a tank. They don’t need heaters like tropical fishes and some can be kept in ponds year-round.

In the US we have a lot of members of the cyprinid family—minnows—that are remarkably easy to care for. They are just like the barbs and rasbora of Asia. These minnows are subdivided into dace, shiners, and chubs. They are shoaling and prefer groups of six or more. North American minnows do best in 30+ gal (113 L) tanks and for the most part are just fine with other species of minnows. My favorites are mountain redbelly dace (Chrosomus oreas), saffron shiner (Notropis rubricroceus), and turquoise shiner (Cyprinella monacha), but these are just the ones I have in my backyard. 

Mountain redbelly dace (Chris Crippen @ Fishbase.org)

For those that like the cute appeal of the corydoras and other tropical catfishes, there are also cute catfish in the streams of North America: the madtoms (Noturus spp). They have the typical catfish look but stay small enough for a 30 + gal (113 L) tank. Some species are spotted or speckled with a bit of color, but their most entertaining qualities are their catfish antics and their adorable whiskered faces peeking out of rock caves.  

Tadpole madtom Noturus gyrinus (Ohio DNS)

Darters (Etheostoma spp) and (Percina spp) are the gems of North America. Hands down I believe they are the most stunning fishes we have here. They have reds, blues, greens, and yellows to match some of the most beautiful tropical fishes. But they have a catch: darters come from cool, flowing water. You have to provide that if you keep them in an aquarium. This often includes powerheads or simply a river manifold. Darters are also territorial, so make sure to provide enough hiding spaces for them in a tank. In the wild, they can just swim down to the next riffle; they don’t have that luxury in a tank. I have seen a few tutorials for how to set up a darter-specific tank like this one from the North American Native Fishes Association (NANFA). Or you could just use a setup typical of hillstream loaches detailed here at Loaches Online. 

Tangerine darter Percina aurantiaca (conservationfisheries.org)

When most people think sunfish, they think about bluegill (Lepomis macrochirus) or crappie (Pomoxis nigromaculatus). These large cichlid-like fish are only a few of the centracidae family found in the US. While not all of them are beautiful, there are a few worth pointing out. The pygmy sunfishes (Elassoma spp) are certainly some of the most stunning. They are the smallest fishes detailed today in this article; they can be kept in tanks as small as 10 gal (37 L). Pygmy sunfishes are also the most delicate and can prove difficult to feed. They are very shy and need a heavily planted tank with things like anarcharis, hornwort, and duckweed. They were once described to me as “not for the fishkeeper who needs to see their fish every day.” Unlike with most of these fish, you probably won’t be able to find pygmy sunfish in your backyard. They are generally restricted to coastal areas of the eastern US. 

Pygmy sunfish Elassoma gilberti male (Erica Wieser @ NANFA.org)

For those that like to see their fish a little more often, there are other more visible sunfish. The banded sunfish (Enneacanthus obesus) and bluespot sunfish (Enneacanthus gloriosus) are a good choice for a medium sized tank. With colors and temperament matching the South American cichlids, they make an excellent fish for a 30 gal (113 L) to 70 gal (265 L) native tank. Unlike the darters and minnows, they prefer the pools to the faster water.

Banded sunfish (Tennessee Aquarium)

Those with a much larger tank might enjoy the some of the most brightly colored Lepomis spp species like the long-eared sunfish (Lepomis megalotis), redbreast sunfish (Lepomis auritus), and pumpkinseed (Lepomis gibbosus). These fishes will need a 100+ gal (378 L) tank as they get large and are territorial much like the larger South American cichlids. These fishes also make interesting alternatives to goldfish and koi in a pond. In clear water their beautiful colors can easily be seen, especially during spawning.

Longear sunfish (Brandon Brown @ NANFA)

The North American fish lineup also includes some livebearers and killifish. While these aren’t the most colorful, they are still interesting to keep in aquariums nonetheless. Some of the best looking are the flagfish (Jordanella floridae), northern studfish (Fundulus catenatus), and the sailfin molly (Poecilia latipinna).

Northern Studfish (Stan Sung @ Aquabotanic.com)

This isn't intended to be a comprehensive guide to North American natives. I just want to open your eyes with this article and let you know there are lots of choices out there. If you have a further interest in these fishes, I highly recommend joining the NANFA forum. I am aware there is a bias in the listings of fish here: they are almost all from the eastern US, but that is where I live. I am most familiar with the fish in my backyard. I encourage you to get familiar with the fish in your backyard no matter where you live. You never know what little beauties you may find!

Works Referenced

"BTDarters." Updated: 26 Jan 2013. Retrieved: 11 May 2013.

"Compatibility and Feeding of North American Native Fishes in Aquaria." Jonah's Aquarium. Updated: 11 May 2008. Retrieved: 11 May 2013. 

"North American Native Fishes: Captive Care." Zimmerman's Fish. Updated: 15 April 2013. Retrieved: 11 May 2013.

Sung, Stan. 2011. "Forest Gems: Fishes of the Streams of the Deep South." www.aquabotanic.com. Retrieved: 11 May 2013.

Divided Betta Tanks

The easiest way to keep multiple bettas!

Everyone knows that bettas need clean, warm water. Personally I don’t like to keep bettas in anything smaller than a 5 gal (19 L) because they are harder to maintain a cycle or proper temperature in. Most people have two to four bettas, and cleaning that many 5 gal (19 L) tanks can take a while. This is why the divided tank is my favorite way to keep bettas.

The Basic Setup

The idea is to separate the bettas by a solid divider. Some people use plastic mesh, and some will use solid glass or plexiglass with tiny holes drilled for water movement. The intention is to physically separate the fish so they cannot touch each other. But the two fish can still see each other.

Left without any visual barriers, they will flare uncontrollably which is stressful to them. This can lead to fin-biting or wasting away. Some fish will refuse to eat and attempt to fight the other fish until they die. This is counter-productive. So you have to obscure their view of each other by placing numerous tall decorations along both sides of the divider. Some people use fake plants; some people use décor like castles and other trinkets. I prefer to use live plants. What is important is that these decorations make it easy for one betta to get out of sight of the other. 

Newly set up divided 10 gallon tank (Pixiefarts @ Flickr)

Other decorations in the tank such as caves should be angled away from the divider to give the bettas more refuge from each other. As always a tank stuffed with decorations and live plants seems to be the best habitat for a betta. In this situation it also gives the bettas ample space to avoid looking at each other.

Most any size tank above 5 gallons (19 L) can be easily divided. The kinds of tanks you want to stay away from dividing are the tall tanks like hexigons. A tall and long tank like a 40 gal (150 L) breeder could be divided, but you would need to provide the bettas ample resting places close to the top. That is a tall tank for a fish with heavy fins. The most commonly divided tanks are 10 gal (38 L), 15 gal (56 L), 15 gal (56 L) long, 20 gal (75 L), and 20 gal (75 L) long.

Variations

There are a couple of variations on this idea, but they all have the basic concept. Some people add multiple dividers to a long tank such as a 20 gal (75 L) long. In a tank like this you could have between three and four (depending on preference) dividers. But you have to take special care to provide the betta in the middle with more than average hiding spaces because he will think he’s being attacked from both sides.

Divided 20 long (Jadesong520 @ photobucket)

Some people take this a step further and create betta barracks. The methods to do this vary greatly from placing a lot of dividers in a tank to having glass custom cut and siliconed into place, but the outcome is the same. There are usually 4+ compartments in the front for bettas and a single large compartment behind the bettas to facilitate water flow, allow for a heater, and a filter. This method is preferred by breeders because it allows you to house hundreds of bettas in a pretty compact area using multiple barracks and industrial shelving racks.

Betta barracks for 10 bettas (LittleBettaFish @ Bettafish.com)

My personal favorite dividing method is the double divider. Instead of just one divider in the tank, I use two to create three compartments, but only two compartments house fish. The middle one houses the heater and filter and a few plants. The additional divider makes it more difficult for the bettas to see each other and also offers a buffer zone in case of a jumper. Bettas are known to jump, and they do jump the divider from time to time. This HAS happened to me before while I was on vacation, but because of this middle buffer zone the bettas did not tear each other apart. They were there for hours until they were discovered. If not for this middle section, I could have come home to one or two dead bettas.

My personal divided betta tank.

View from the side. Note how opaque the divider is.

Problems

No setup is perfect and when you put two bettas in a tank together (even with a divider) you still have the potential for problems. As I was just talking about with my tank, jumping is a serious issue. Just last week a friend of mine who also has divided tanks lost one of her bettas when the other jumped the divider and beat him to death. The double divider is one way to help prevent that. The other thing you can do is make a jump guard. Because I made my dividers from craft mesh, which is bought in sets of multiple sheets, I had some left over. I cut the leftover mesh to make a jump guard. It’s just a piece of mesh that rests on top of the divider and hangs out over the edges about 3 inches (7 cm). If a betta jumps at the divider, he or she will just hit the mesh.

Jump guard made with craft mesh.

Another issue is the spread of waterborne diseases like ich, fungus, and columnaris. If one fish gets sick you have to treat the whole tank for it because the other betta (or bettas) have been exposed. Most disease can be prevented by having a good quarantine regimen.

Sometimes you will just get males or females that just can’t handle living in a divided tank. Even with lots of plants along the divider they will fin-bite or pace all day, trying to get away. Generally the bettas that are more relaxed tend to do better in divided tanks. Having two very aggressive bettas in a divided tank can be a problem. This is a specialized setup; it isn’t for every betta.

As I have said before this is my favorite way to keep bettas. You get double the fish for the same amount of maintenance. My betta tank gets one 30% water change weekly and takes the least time of all of my tanks. I highly recommend this type of setup to anyone. I leave you with a video of my divided betta tank. The two males do not notice each other at all.