Possible Fin Rot. Help Please

[MegaZerino]

I think my betta may have fin rot, im not sure, which is why i would like to check before i start treating him, also, can i treat him in the tank along with the rest of the fish because i dont have a spare tank.

Tank size: 125 litres
pH: 7.1
ammonia: 0
nitrite: 0
nitrate: 150 (not sure why, its a new tank with completley new, clean water, but the filter is from the old tank so is flly cycled)
tank temp: 26-27 degrees

Fish Symptoms (include full description including lesion, color, location, fish behavior): he is acting the same as he always does, i noticed a few days ago but assumed it was just the lighting. I set up my new tank yesterday (125 litres, he came from my 65 litre), so all the fish are new, but they couldnt have been carrying bacteria because it wouldnt have had time to spread. The tips of a few of his back tail fin strands are starting to go brown, and a few have started to curl. hew has not been scratching against anything.

Volume and Frequency of water changes: in the old tank i did 20% changes weekly

Chemical Additives or Media in your tank: i use JBL's plant fertiliser but i was using it before he had it, and i have carbon in my filter

Tank inhabitants: in the old 65 litre there was him 4 female bettas, 1 dwarf gourami, 5 snails and 3 ottos. In the new 125 litre there's 6 peppered corys, 3 pygmy corys, 3 ottos, 2 butterfly rams, 1 dwarf gourami, 6 galaxy rasboras, 4 snails and 10 chili rasbora.

Recent additions to your tank (living or decoration): ive used all the plants from my old tank, and the new inhabbitants are the corys, rams and rasboras

Exposure to chemicals: none

Digital photo (include if possible): he moves to fast for my camera

 

[onidrase]

you should really get those nitrates down, 150 is ridiculously high, regardless of whether or not you know why they're so high. It might even just be the water quality causing the issues. Do some good water changes, and watch to see if it gets any better or worse.

 

[MegaZerino]

you should really get those nitrates down, 150 is ridiculously high, regardless of whether or not you know why they're so high. It might even just be the water quality causing the issues. Do some good water changes, and watch to see if it gets any better or worse.

yh, im going to get some stuff to bring it down tomorrow, im also going to see if they have anything for the finrot

 

[Flubberlump]

You still need to do a large water change to remove some of the nitrates. That is the easiest and probably most efficient way to bring the levels down. You should do it ASAP, then test the nitrate levels again once the new and old water have had time to circulate and mix.

 

[MegaZerino]

You still need to do a large water change to remove some of the nitrates. That is the easiest and probably most efficient way to bring the levels down. You should do it ASAP, then test the nitrate levels again once the new and old water have had time to circulate and mix.

i did a 40% change a couple of hours ago, im gunna do a test when i get home from school tomorrow