This is going to be a long post, and I am very aware that I've made quite a few mistakes with my tanks. I'm hoping for some advice to help me make the best choices for my fish going forward.
I've got two tanks right now, one five-gallon with a betta that is about a year old and one 20 gallon with flag fish and platys that is about 10 months old, both planted, and both are a huge mess of problems.
Both were semi-impulsive projects, where I thought I had done all the research, but I've run into persistent problems with both, and I hope I can get some advice.
I believe the 20gal is badly overstocked. At last count, there are 5 Platys, 3 flag fish, 1 clown pleco, and an African Dwarf Frog. The Platys keep reproducing, most of the adults have ragged fins that I believe are from the flag fish nipping at them. The tank itself has a serious BGA problem, that I haven't been able to fix with blackouts. It's a natural planted tank, but I was talked into using peat moss instead of organic soil, and I believe that that might be part of the problem. The other part, being of course, that the tank has too many fish and not enough water changes. I've been trying to do weekly ~40-50% changes, but it often ended up being closer to every week and a half instead.
My current plan is to break the tank down completely and scrub all of the algae away, replace the peat with dirt new sand, replace the worst off of the plants and find somewhere to rehome the majority of the fish.
I feel terrible about the fish; if I could afford a third tank and had room for it, I would almost rather do that instead, but I just don't have the resources. I know Petco has a fish adoption program, but my local petco's fish section was TERRIBLE last time I went there, the betta display was full of dead and dying bettas, and the snail tank was full of dead snails, and I'm not sure if I'm comfortable leaving animals there that are meant to be my responsibility. If anyone has any ideas on where I can find good homes for my fish, quickly and locally, I would really appreciate it, on top of any opinions about my plans for the tank.
The Betta tank is a little better. The water is more regularly changed, still closer to 50% every week and a half than weekly, but the real problem is I have a bad problem with brown algae that was never a problem in my larger tank. The tank is acrylic, so I can't scrape it down with the metal algae scraper, and the scrubber pads don't work very well.
My plan for this tank is to move my Betta to a 10-gallon (GLASS!) planted tank and either divide it, or see how he does with a very few small, peaceful fish.
He used to share his five gallon tank with an oto, which was another bad idea, as the tank was too small and he harassed it until it harassed him back; but once I rehomed the Oto, he started biting his own tail regularly, and I've already had to deal with fin rot with him before(he had a touch of it on his fins when I got him, and it keeps coming back) I think the problem is that he is bored, and I'm not sure how to fix that.
I'm hoping it'll be easier to keep a 10 gallon clean, and that a tank mate in a divided tank will give him something to be aggressive at other than his own tail. At the very least, a glass tank will be easier to clean.
I'm hoping someone can give me some advice on what to do for his tank, or what I can do to help with the tail-biting.