http://bettafishcaretaker.com - All Betta fish need tropical water temperatures. If your tank isn't at room temperature of 72-80 Fahrenheit.. then you need a heater. I have my half moon beta in a 1 gallon tank right now because he ripped his fin pretty good on the fake plants that I had in his 10 gallon home. He also had some bad decorations, he probably cut it on one of those. So I moved him out so that he could heal. He has been in his little tank for about 4 days now and I do 15% water changes every day. Keeping his water clean is what I was told for fin rot. I bought a mini heater and it seems to keep his water at 80. I have to unplug it because it has gotten to 82 and I don't want fish soup. Poor guy. What temperature is too hot? There is no gauge to keep where I could set temperature. http://goldfish-facts.com/turning-brown-white-black-spots/ I have 2 beta fish. One in a 10 gallon tank with 3 red eye tetras, and a cory. For the most part they get along. I will see my beta flare at them and follow them about the tank but nothing bad. The cory just does his thing. I have another beta in another 10 gallon tank but he is in my sons room. His tank has the beta, 3 Penguin tetras, and a small cory. The penguin tetras are very shy. They like hiding in the plants. They hide when ever I come into the room to watch them. That beta is also doing well with his tank mates. Not sure if thats what you meant by can you mix beta fish. You definitely can't put more than one male fish in the same tank though. Where they produce eggs for breeding but they don't/can't release them. Thanks, I just looked it up....would 4 out of my 6 girls do this at the same time? That's what's worrying me. Also no males anywhere. Well there is a halfmoon, a unknown and 3 crowntails, the cts are the worst, the halfmoon only slightly and the other is fine. CTs are known for egging up very easily. You're overfeeding them if there is no male and it's that much. Fast them.. It can take up to two weeks no food at all to reduce that. Is there a maximum tank size for a single betta? I have him in a 10 gallon and he lives a good life. But I have a 75 gallon and it's just sitting around for now. Is that too big? Is it possible for a fish to like a small, non-heated, unfiltered tank better than a 10g with all the perks!? I am convinced that my guy is biting. It has to be. I've changed all the decor to silk, baffled the filter and verified that the tank is cycled. I've done weekly 30% water changes and temp is around 80 degrees. When I saw the fin issue at first I moved him to a 1 gallon to change his decor and make sure my cycle wasn't screwed. While he was in there he blew big bubble nests and his fins seemed to be ok. Back in the big tank, day later his fins looked like poop again! Back to the small tank he was happy as a clam again! This time I tried treating him for fin rot and after a while his fins seemed better. I had ordered the sponges for the filter and back in the big tank he went. Now yesterday I found him all shredded again! WTH!? And in the small tank he blows a nest every day. He has never made a nest in the big tank. I know that's more about sexual maturity but it seems like it would have at least a little to do with his satisfaction of his environment, wouldn't it? And his fins seem good when he's in the little tank. Should I move him permanently to a smaller tank?? Or put a smaller bowl in his big tank?? Try to entertain him more? Help!