Very rapid breathing from zebra dannio

[Tttay89]

110 litre
Ammonia 0
Nitrite 0
Nitrate 15
Ph 7.2
Temp 26
Water 50/50 RO and tap changing 30% weekly

Good water movement and filtration show up as 8/10 on oxygen test kit. Air stone in the tank along with the filter bubbler.

One of my 4 dannios has started breathing very rapidly, around 5 breaths a second I'd say. Started yesterday. The dannios being my longest standing fish since I had the tank.
Still eating and swimming normally

Nothing bullies them they're just in their own happy world

I did purchase a julidochromis fish a couple weeks ago which I don't have another tank to quarantine so I'm thinking this could be a cause?
I can't see any signs of disease and redness worn away gills bulging eyes etc...just the very rapid breathing from the mouth and gills.

Any suggestions?

Thanks

 

[FishGuest5123]

You can add some aquarium salt at 1 tablespoon for every 5 gallons. Be sure to dissolve it in a little tank water first. Aquarium salt helps improve gill function.

 

[Tttay89]

Ok just bought some I'll add when I get home. If it did happen to be a disease from the new fish is it at all possible for the new fish to not have symptoms but the dannio to get them ?

 

[FishGuest5123]

Ok just bought some I'll add when I get home. If it did happen to be a disease from the new fish is it at all possible for the new fish to not have symptoms but the dannio to get them ?

If the Danio already had stress it could affect it’s immune system. Perhaps it’s just stressed from the new neighbors.

 

[Tttay89]

Hmm...day 3 with the salt and still struggling...

Any more suggestions? ...

Just bizzare how he's still eating fine and swimming normally