I've been keeping fish for around 6 years now and consider myself of moderate to advanced ability. I got started during my senior year of high school. My biology teacher wanted us to do an experiment that wasn't the same old ones that high schoolers always perform. I chose to see if a fish could run a maze like a mouse can. Well for some unknown reason I chose koi (Cyprinius carpio). In case you are wondering, no. They couldn't run the maze like I thought they would. Anyway, I overwintered them in a heavily filtered 55 gallon tank, and come springtime of my senior year we built a 4000 gallon koi pond in my backyard. Odd that I should start so large and work my way down.
With the koi in the pond, I added two fancy goldfish (Carassius auratus auratus) to my 55 gallon tank. They are still there. When I went away to college I bought myself a Siamese fighting fish (Betta splendens) to keep me company in my dorm and kept him in a heated and filtered 5 gallon tank. I burned up a ton of gas coming home to look after my goldfish and koi, but it was worth it. In college I studied fisheries science and also received a minor in biology. Most of my formal education actually dealt very little with my hobby. The only parts that I have been able to carry over have been fish physiology.
In the area of fish tanks I currently have my 55 gallon goldfish tank with two goldfish about 6 years old: a calico veiltail and a red and white ryukin. Currently the tank is sparsely planted. I have two divided 10 gallon betta tanks with two males per tank. My mid-sized tank is a 29 gallon tank that houses my population of kuhli loaches (Pangio spp). And the koi pond with 6 koi and a reproducing population of mosquito fish (Gambusia holbrooki). I will post more in-depth articles about my tanks later and will be sure to update them as my tanks change. For now, I leave you with a photo of my koi pond from last summer.