Betta Acting Oddly

[Arok Lazarus]

Hello all! I recently finally got my fish tank set up and its a nice 5 gallons with my betta and 3 neon tetras in it. Unfortunately, I didn't notice that until after I bought my betta, Hoth, that he is missing one of his fins. Its his right one that's under his head. I'm treating him with melafix (I noticed blood the first day I had him which is when I noticed the missing fin). And so far he acts normal. All of today though I've noticed that he likes to rest directly on top of my tank's heater. It's not hot enough to cause him damage (it shouldn't be at least) so I can only assume it must feel good to him/his missing fin area. Should I be worried about this?

 

[librarygirl]

What temperature is the tank? Bettas like it warmer, 78-80 degrees, if the tank is too cold that could be one reason. Also be careful with Melafix; too much can be harmful to bettas which have a labyrinth organ. Aquarium salt and clean water (some extra water changes) should be enough to help the fin heal.

Also is the tank cycled? How new is the tank? What are the water parameters (ammonia, nitrite, nitrate)? Any high levels of those can cause the fish to act oddly and can cause fin rot issues. And just FYI a 5 gal is way too small for neons as they are active fish that need a large group and a good amount of horizontal swim space.

Here are some links for you:
https://www.aquariumadvice.com/guide-to-starting-a-freshwater-aquarium/
https://www.aquariumadvice.com/arti...g-but-I-already-have-fish-What-now/Page2.html

 

[Arok Lazarus]

My tank is at a constant 78 degrees. The tank is a couple months old as it temporarily housed a Molly but I've had this betta for almost 2 weeks now. I cycled the tank for a day after having removed the Molly. My betta is often at the bottom of the tank or on top of the heater (although he surprisingly hasn't done that today). I did move the decorations around so maybe he's trying to get more comfy.

I won't be able to test my water for a few days but the Tetras in there seem to be acting just normal so I don't imagine its a significant water issue. I think a lot of it may stem from his missing fin. How much salt would you recommend? I don't want to put too much in there that the Tetra's might get affected negatively and I understand that Tetra's are more sensitive to salt.

Thanks!