Okay, all of my tetra's stick together for the most part. Usually when I buy them I buy no less than three. But I have gotten these a long time ago, almost a year ago when I had a little 20 gallon. But then I decided my turtle needed the extra space more than me needing two tanks, so I combined the two into the bigger tank and a couple died thanks to an old tiger barb I used to have(very agressive and big) I used to have two but the other tiger barb died of unknown reasons. So when I watch my tank, all four of the tetras, the danios, plus a rasbora(forgot about that one) stick together. The tiger barb goes back and forth between the sharks and the gouramis.
My tank is one of those hexagonal tanks, and is reletively tall. So the water at the bottom tends to be a bit cooler than the water at the top. When I got my dojo, he looked close to dying. But when they tried to net him, he would swim away. So I figured it was the temperature. But I decided to bring him home anyway, since I allready had one dojo, I had been dying to get another. When I brought him home I put him in a floating breeding trap to keep him away from everyone else, and then once he perked up I put him in the tank, and I have had him ever since(a little over a year) and he seems happy.
My iridescent sharks are my favorite of the tank. About three years ago when I got my first tank(a little ten gallon) all my fish would die soon after I bought them, which was probably because of my lack of experience, and one of my sharks was the first fish to survive, and after that most of the fish I got thrived, and then I got my new tank, about two and a half years ago. And she is about 5 inches but hasnt got much bigger. And I have yet to lose a fish to her. She is far from agressive. Back when I had my ten gallon, I figued I must be doing something right, because she layed eggs, and I had heard that they dont in captivity. When I got the tank I have now, I got another so she would have a buddy, and they swim around together. But the one I got is a bit smaller and doesnt have eyes. When I got him he did, but one day I noticed they were gone! I have no idea what caused this, but he gets along fine and eats and everything.
Yes the African butterfly. I used to have two, but one died, probably because the other used to pick on him.
I used to have 6 corey in that tank, but then I had various issues with my tank. (such as once when the tank had gotten a bit cold, I turned up the heater, and I usually check it before I go to bed to make sure I didnt turn it up to much and I had fallen asleep before Igot to check it and in the morning it was WAY too hot and a few of them had died. Luckily though I had only lost 3 fish all together.)
I usually test my water for ammonia, nitrates, nitrites, and Ph.
I usually take out about a quarter of the water, sometime less. So about 20- 30% I guess.
And yes I always use a declorinator.
I usually clean the tank this thoroughly about once a month or so. And I have an external filter.
I hope you don't do all that at the same time. especially water changes and filter cleanings. filters and the water have important bacteria in them and if you change clean them both it could cause an imbalance between bad bacteria and the bacteria that fights it. I'm not an expert or anything but just from doing research my self i have read that it is not good or necessary to take the fish out to clean your tank. it puts a lot of stress on them. i'm sorry for your loss i too just lost a gourami last week.
I usually do it all at the same time, I never knew it was bad. Everything I know, I pretty much learned from a friend, even though my tank does better than hers usually.
The only reason I take out the fish, is because the vaccum I have is very large, and I would rather stress them out by taking them out instead of accidentally sucking one up. My tank is very tall but not wide, so there isnt a lot of space for me to get my vaccum in there without disturbing everyone. And the one time I did try it, they pay no head to me and just keep swimming in the way of the vaccuum.
Oh, and I am sorry about your gourami. I love my gouramis, I plan on getting biig tank for mostly gouramis one day.
Here are some pictures of the gang.