can same water cause different impact on 2 fishes

[marcusbacus]

My blue betta today has some bits of his tail literally destroyed (it's not a huge area, and there arent spots or any other weird things, it's under control I hope), and I read that fin rot usually can be caused by bacteria or acid water. As the water I'm using is being treated the same way for my 2 bettas (and it's quite alcaline when it comes from the tap!) and the other one doesnt have any sign of tearing, can the same water have a different impact on each one or I'm just paranoid?

I think this is not fin rot, because this betta is *extremely* active - last night I caught him trying to swim between the thermometer (which has a suction cup) and the glass, in a space that is small even for a neon... "eat less and you'll be able to do that!"... I am not sure but when I fed him earlier this morning the "damage" wasn't so big, but yesterday I had noticed that there was a small bit of the tail starting to "rip", probably due to manipulation as I did a full water change yesterday.

Everything seems to be normal, temp is ok, he's eating fine, flaring, there is a monster bubble nest (not usual with him, it's always scattered), etc. etc. so I'm guessing he just needs some sleeping pills

[twoluvcats]

I have a hyper betta whose tail is always suffering from his contortions. Make sure that all his decorations in his tank pass the betta test (run pantyhose over them...if it snags, it'll rip your betts tail), and just keep an eye on the torn spots for fin rot...darkening or redness of the fin edges. If he's lost a lot of tail, treating with melafix can help stave off fin-rot and support fin regrowth.

How close are your 2 tanks...putting them near each other might give your hyper betta something else to do besides getting himself wedged in innappropriate places...he'll have someone else to worry about.

[marcusbacus]

His tank has no decoration but some gravel, and a heater and a thermometer. The tanks are side by side and I'm using a paper sheet to isolate them, and I remove the sheet when it's time for some exercising. Even with the sheet, he doesn't seem to be quiet during the day, and at night when he's really exhausted he lays on top of the heater or besides it, in some darker area and doesn't move until the next day... I guess! He's already medicated, just in case. He once had some small(er) bit of the tail ripped off (my mistake that time!) but I saw that bit being "detached" and saw it fall on the tank, but this time I didn't find any tail pieces, hence the worrying.

[Jenova]

Couldn't it be the water quality?

What are the ammonia levels in his tank?

[marcusbacus]

I didnt measure it today, but I did a full water change yesterday and the water that was used was 0. It doesn't seem to be anything serious, since he's still (hyper)active.

Update: I just tested the ammonia, it's 0.