Awhile back my wife got a betta fish in one of those small 1 gallon tanks with no filtration or heating. Last week we upgraded the tank to a 10gallon with a heater and filter. I was reading somewhere about using a water bottle to minimize the water flow of the filter and it seemed to work well. We put the betta into his new home last night. We watched him for a few hours and he seemed to really like his new home. Everything seems to be going really good until this morning. This morning I noticed his fins were torn in multiple places. I watched him closer and he seems to flare up around the heater and then thrash around and catches his fins on the plastic of "make shift water bottle flow minimizer". I've removed the plants around that area and cut the plastic of the bottle a bit more so it doesn't hang down into the water so much but he's still swimming around the heater, flaring up occasionally and thrashing around. Im starting to get worried about what this may do to the betta and if this may cause any diseases or possible death. His fins are in very bad shape and i'm wondering if I should go get the betta some medication.
Any advice would be appreciated!
Thanks in advance!!!