I have a male betta that I purchased from LFS 9 days ago. He was housed in a tank with filter and heater set to 76 with 2 platies and a molly, the platies and molly were not meant for that tank but my main tank where I had an issue with a dalmatian molly bullying so this was temporary until I can rehome them. He wouldn't leave the platies alone and I had to take them out after a few hours or id have a dead platy. The day after I noticed he was not coming out much and just kept hiding and just didn't seem right as did my molly. Out of panic I put him into a floating box into my other tank which is a female betta tank ( I know not to keep them together but I had no other set up and the molly died) i shut down my other tank which was given to me by a friend 2 months before and had been set up for that time too but in my panic didn't test the water.
My male seemed to have perked up for a day or so in the float box and even blew a bubble nest. I ordered a divider for this tank for them but its not arrived yet and I didn't want to risk putting him back into the other tank in case it was contaminated in some way and I don't have funds to start a completely new set up.
Meanwhile he's got clamped fins and his clear colouring on the edges of his tail have got a reddish tinge and he's not very active. I bought some king british disease clear which I dosed on Monday as I'd read it may be fin rot, I can't see any ick or gold dust for velvet. He's still eating and pooping but he's been like this for 4 days now.
I'm just hoping someone could tell from the photos what it could be. I'm awaiting my water test kit to arrive today but my girls all seem fine including the platies that I had to put back in this tank for the moment.
I'm a bit confused, possibly because I forgot to drink my daily coffee! It probably won't affect the advice I give but I like to visualise the situation so that I can provide appropriate advice. How many tanks do/did you have - is it..?: Tank 1: A bullying dalmation molly (to be rehomed or dead) plus 2 platies (to be rehomed) and another molly (now dead or to be rehomed). Now shut down and tank to be returned to friend. Tank 2: Tank intended for male betta only but which also had the 2 platies - this wasn't working out so male betta moved to Tank 3 in a breeding box plus the two platies. Now empty but worried that contaminated. Tank 3: Female betta tank, with male betta in a breeding box in it, plus the 2 platies and a bullying/non-bullying molly. Grateful if you can confirm.
WRT the betta, I think he's most likely stressed at being cooped-up in the breeding box with a sorority of females tempting him, and he's most likely biting/shredding his tail. Why do you think that one of the tanks is contaminated? If it weren't, the logical solution would be to move him back in there.
If you can clarify the situation about who was in each tank and where they are now, I might be able to help better with logistics of who should go where; thanks. :)