The tank is a 29 gl., an AQUEON Quiet Flow30 (for tanks up to 45 gl), sand is from petsmart - the black fine grain stuff, one large plastic plant from walmart, a fake twisted branch from walmart. Water changes are done weekly, treated with Nutrafin Aqua+plus, and Nutrafin Cycle. I have a heater that's set at 78-79. I have 14 baby betas, that's all. Tank was set up first week of January. Bought all the female betas at the same time, as petsmart had a sale - and they were all around 1" long. All got along fine until one started growing extremely faster than the others. I took it out and put in a 3 gallon tk. Anyway, two days now, I noticed two of the smaller ones look like they have collapse fin/tail. QUESTION: should I medicate the whole tank or just pull those out and put into quarentine tank? And what meds should be used? Most say on bottle that betas and tetras and small fry to be med at half dosage. Please answer asap. TIA TRACY