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.

My Tanks: 15 Feb Update

Wow. It's been a long time since an update, and I have a lot to tell. There will be a lot of pictures.

Community Tank

The biggest changes have been in the 29 gal community. It is almost completely stocked. In the beginning of January I ordered my Farlowella acus from Invertibrates by Msjinkzd. Since I knew it might still be a while before there was some color and movement in the tank I also ordered a handful of red cherry shrimp (Neocaridina heteropoda var. red) to add some movement and color. Everyone arrived safe and in great health; I highly recommend buying from this seller! I know I will be a repeat customer. Just take a look at what she sent me! 

Farlowella acus on his first week in the tank. He's cleaned up that algae now.

From the side. The seller did an excellent job of making sure he was eating
before selling him. Comes off his wood when the algae wafers go down.

One of my female RCS just a few days after introduction. She is now berried.

The crypts that I added back in December have really taken off. Both plants have very little melting, and I see lots of new leaves. The tiger lily did not make it. It showed good growth for a few weeks and then the leaves just withered away and never came back. I noticed a problem with the flow behind the smaller piece of driftwood, and had to move the wood and the dwarf sag and pygmy chain sword that was behind it. The sword never recovered and my other sword that was in the tank died off, too. The dwarf sag is slowly recovering, but I don't think it will ever do well there. So I'm looking to put some more crypts on the right side later this year.

In the beginning of February I ordered kuhli loaches (Pangio oblonga) and a trio of honey gourami (Trichogaster chuna) from The Wet Spot in Oregon. Everyone came through quarantine without a hitch so they were put in the main tank a week after they arrived. In fact, they actually spawned twice in the QT to give you an indication of the health of the fish when they arrived. The Wet Spot is another seller I highly recommend.

Full tank shot. You can see the male just to the left of the wood.

One of the females defending her position.

My male gourami trying to romance one of the females.

I believe this is one of the new loaches. It's rare that I get
a picture of them at all, so a butt shot will have to do!

Other tanks

Not too much has changed in my betta and goldfish tanks. I removed the fake floating plants in the goldfish tank since the live plants have grown large enough to fight the current from the filters. It took the goldfish a little bit to get used to, but they're adjusted now.

In the betta tanks I've replaced the home-made sponge filters with Hydro II sponge filters. I noticed some algae issues a few months back and decided I needed a bit more flow. The Hydro II's have give that to me but still keep the flow low enough for the bettas. It's a win-win!

And I did a bit of decorating both tanks for Valentine's Day!

Goldfish tank! Pardon the algae on the back wall.

Hearts on the betta tank! They flared at them for a few minutes.

My last bit of news is a plan to set up a new tank! The plants in my second betta tank just never did well. So I'm breaking down that setup, finding new homes for the bettas and setting up a dedicated red cherry shrimp tank! Those little shrimps were just supposed to be a placeholder until I could get some movement in the tank, but I've fallen in love with them. I have seen the female RCS holding eggs in the community, but I've never seen the babies. I'm pretty sure the fish are eating them. So instead of fighting nature I'm going to dedicate a tank to my shrimps!

That Kiss!

Not all is well in paradise.. 

A Valentine's Day draws near I’m seeing more pictures and .gifs of the trademark behavior of the kissing gourami. I’ve also heard a few people planning to purchase these fish as gifts for loved ones. Neither of these actions are as sweet as you might think. I’ll explain why.

The kissing gourami is a unique gourami in that it is the only species in its family Helostomatidae. They lack the long ventral fins of other common gourami but still maintain that gourami attitude. They are feisty and will put on displays to keep others from their territory, but they display by lip-locking. This appears to people as if the fish are kissing, but they are actually fighting to drive the other fish off; they push against each other until one fish backs down and swims away.

Kissing gourami in a territorial dispute (Tom Bailey Photography)

The thick lips of the kissing gourami were originally developed for rasping algae and other microorganisms from branches and leaves in their ancestral swamps. In the aquarium they will do this to plants as well as the walls. This is why you will often see them “kissing” everything in the tank. Because they have such powerful jaws, they will often tear up the leaves of plants in attempt to eat what grows on the surface.  As they grow, they will consume smaller fish that they are housed with like small tetra, danio, and rasbora.

Mouth detail of wild form (Seriously Fish)

This fish also gets much larger than most of the common gourami. What you see in the small store tank are just the juveniles. Most specimens top out between 10 inches (25 cm) and 12 inches (30 cm) long. Tropical Fish Hobbyist magazine recommends a 75 gal (283 L) as the minimum size for a single adult; groups need much larger tanks. When they are fully grown, those two little babies that used to ‘kiss’ each other will be large and territorial. It’s not uncommon for the larger fish to harass the smaller one to death. This is not to say they can’t be kept together, but two fish almost a foot long each require a lot of space to ensure each fish has its own territory.

Now you may be thinking that I just ruined your Valentine’s idea for the fish-lover in your life. But fear not, for he or she would have been very unhappy if you put two of these fish in her or his tank without asking first. There are much better ideas, and I don’t mean a red betta in a vase. I’ve seen some small heart-shaped aquarium decorations that would be darling to surprise your fish-lover with. Nothing like waking up and finding a heart in you aquarium to know someone loves you. Gift cards are another great option especially if you know that special someone is looking for a specific item. And there is always jewelry. I’ve seen some very beautiful fish necklaces and earrings.

Silver red crystal fish pendant
(maxjewelrystore.com)

So this weekend when you are out shopping for that special someone in your life, leave the kissing gourami in the store. Your fish tank (and your significant other) will thank you for it. Most tanks can't house a surprise belligerent 10 inch (25 cm) fish that eats your aquascape and tetra. 

Works Referenced

"Helostoma temminkii, Kissing gourami." fishbase.org. Updated: 3 July 2012 Retrieved: 7 Feb 2013.  

"Helostoma temminkii (Kissing gourami)." Seriously Fish. Updated: 2013  Retrieved: 7 Feb 2013. 

"Kissing Gourami Fish." Fishchannel.com. Updated: 2013 Retrieved: 7 Feb 2013

Is my fish a girl or a boy?

How to determine the sex of your fish

Most people like to name their fish and want to have a name that fits the fish’s gender. Other people want to try breeding and need to know if they have males and females. Sexing fish can be a tricky thing, but there are some species and families of fish that are relatively easy. Before we get into those, I’ll talk about some general trends in sexing fish.

Females are rounder

Of course this only works with mature animals, but for the most part the female will have slightly thicker bodies. This is because the eggs that females carry take up more space than sperm. The females also need larger fat reserves to produce the eggs.

Males are smaller and more colorful

Just as in birds, males are the more colorful of the genders. Males compete with other males by showing off their vibrant colors. The most colorful male gets to mate. They are also slightly smaller than the females.

Sexing popular fish

Goldfish (Carassius auratus auratus)

These fish can actually be a little tricky as they have no obvious differences when the fish are not breeding, but there are two things you can look for when they breed: breeding stars and the shape of the vent.

Breeding stars or breeding tubercules will only appear on the males. They appear on the gill plate and pectoral fins. These are a sign of virility, and a study performed on a relative of the goldfish found a correlation between the number of breeding stars and how healthy a male fish is. These stars help a female fish decide who she wants to mate with.

Breeding stars on pectoral fin and gill cover (goldy fk @ flickr)

The next thing to look for is the shape of the vent (this is also called the cloaca and is the opening near the anal fin). The vent of the male will be slightly larger and concave (meaning it curves inward). The vent of the female will be smaller and protrude slightly. The pictures below better illustrate this.

Circled male vent (mikroll @ TheGAB)

Circled female vent (mikroll @ TheGAB.org)

I find using the vent method to be a little difficult as my goldfish usually like to have their heads facing towards me begging for food. I prefer to use the breeding star method because they are more visible in my experience.

Betta fish (Betta splendens)

These small, popular tropical fish are a little easier than goldfish to sex because some of it can be done out of the breeding season. There are two main ways to sex bettas: fin length and the presence of an ovipositor.

If you see a long-finned betta it is a male. There have been cases where females have longer than normal fins, but they aren’t nearly as long as the typical halfmoon spread seen below.

These extremely long fins indicate a male(Aquariumloto @ Flickr)

Sexing bettas gets a little trickier when you are dealing with plakat (or short-finned) bettas because the male and female fins are the same length. Now you have to look for the ovipositor on the female. The ovipositor is a small white tube protruding from the vent of the female; in breeding she uses this to position eggs. It will appear as a small white dot behind the ventral fins. The lack of such indicates a male.

Arrow points to ovipositor (Stuart Halliday)

Angelfish (Pterophyllum spp)

Another extremely popular aquarium fish, but much harder than bettas or goldfish to sex. They have no discernible differences when they are not spawning, and when they are spawning you have to look very closely to see the only difference:  the males will have a thinner breeding tube which is visible in the vent of the fish. Both males and females have breeding tubes, so the key is to look for the smaller one.

Female angelfish breeding tube (koiangelfish.com)

Male angelfish breeding tube (koiangelfish.com)

Neon tetra (Paracheirodon innesi)

Like angelfish, neon tetra are difficult to sex. The only difference will be in size. The females will be slightly larger and fatter especially when they are ready to breed. Males may show slightly better color, but these differences are so minute that they will likely go unnoticed.

Livebearers (Poecilidae)

These are fish like guppies, platies, swordtails, and mollies. The males and females are very easy to tell apart. There is a large size difference with some females being almost one and a half times the size of the males. The males will have long, flowing fins and are very colorful. Males also possess a modified anal fin called a gonopodium; this is used to transfer sperm to the females. Below you can see two illustrations showing the differences between male and female guppies

General female livebearer characteristics (jabraguppyroom.blogspot.com)

General male livebearer characteristics (jabraguppyroom.blogspot.com)

Cory catfish (Corydoras spp)

Another popular but difficult fish to sex, cories have no highly visible differences between the genders. Females will tend to be the larger ones and look much chubbier when they are breeding, but for the most part males and females look exactly alike.

Bristlenose pleco (Ancistrus spp)

These small plecos are surprisingly easy to sex. Both males and females will have the bristly nose, but the number and size of the bristles will be much greater in the males. This is especially true when the fish are in breeding condition. Scientists believe that males evolved the bristles to mimic young fish because females are more likely to mate with a male who is already caring for eggs.

Male bristlenose with month old offspring (goldy fk @ Flickr)

Oscar (Astronotus ocellatus)

Probably the most popular of the cichlids next to angelfish, but even more difficult to sex. Among wild populations the males show more color than females, but this isn’t reliable with the captive-bred fish that show up in stores nowadays because they have been bred for color.

Cherry barb (Puntius titteya)

This is a species that is easy to sex based on the general trends in fish genders. The males are smaller and have more red color and the females are larger and will be more brown in color. This holds true with wild-caught and naturally bred cherry barbs. There are some that have been specifically bred to make the red even brighter; these are much more difficult to gender. 

Female cherry barb on left, male on right (aquapage.cz)

Gourami

They aren’t as easy to sex as livebearers, but they are pretty easy if you know what to look for. If it’s not a captive-bred variant, the males will be a brighter color especially when breeding. If they are a color variant you have to look for a few other things. For the Trichogaster gourami (this is dwarf, honey, thicklips, and banded) look at the end of the dorsal fin; males will have a pointed dorsal, and females will have a rounded dorsal. These pictures below illustrate this as it can be hard to pick out if you’ve never seen it.

Male honey gourami (CK Yeo @ Flickr)

Female honey gourami (CK Yeo @ Flickr)

For the Trichopodus gourami (opaline, three-spot, blue, gold, pearl, and moonlight) you also look at the dorsal fin. The males will have a longer dorsal fin. Males of the pearl and moonlight species will show more red color than the females.

Pearl gourami. Male above, female below (seriouslyfish.com)

With some of our aquarium fish it can be very easy to tell the males from the females, but others can give you a lot of trouble. Some like oscars and angelfish can even give breeders trouble in determining gender. If you wish to breed any of these fish, I highly suggest you do a lot of research and read personal experiences. While breeding can be fun and rewarding, it can also be costly and heartbreaking when done incorrectly.

Works referenced

Christie F. 2006. Sexing Bettas: The Ovipositor. nippyfish.net. Retrieved: 31 Jan 2013

How to tell Male and Female Guppy Apart. Jabraguppyroom.blogspot.com. Updated: 29 July 2011. Retrieved: 1 Feb 2013.

Kortet R., J. Taskinen, A. Vainikka, and H. Ylonen. 2004. Breeding Tubercles, Papillomatosis and Dominance Behavior of Male Roach (Rutilus rutilus) During the Spawning Period. Ethology 110:591-601.

Seriously Fish

Sexing Angelfish. Koiangelfish.com. Updated: 2013. Retrieved: 1 Feb 2013. 

Sexing Goldfish. Bristol-aquarists.org.uk. Updated: 26 October 2012. Retrieved: 31 Jan 2013

Sexing Goldfish. theGAB.org. Updated: 16 Aug 2009. Retrieved: 31 Jan 2013