Fish can't swallow food bigger than lobster eggs

[TheStripedHermit]

It's been almost an entire month in quarantine since this has happened as in the first week it was eating half a cube of brine shrimp like a champ until it progressively was unable to swallow more and more, till only eating the largest soft ones before unable to swallow any at all. I even tried giving it some krill as well.

Apart from lobster eggs and copepods, it can't eat swallow anything bigger than this and if it takes a gulp of a cluster of these foods it spits them out, only able to eat them mostly one by one.

And to top this off the fish looks perfectly healthy as it's not really gilling, no lesions or markings on it's skin, no flashing, scraping, nothing like of that.

But even with a freshwater dip, two doeses of prazipro and currently treating with fluebendazole there is no noticeable improvement at all.

So anyone have an idea what could be going on? Tank is running at a salinity of 1.018 with nitrates, ammonia and nitrites being undetectable.

 

[Sailfin11]

What type of fish is it?

 

[vetteguy53081]

Even though fish will eat at hyposalinity, I suspect the salinity may be issue in part (raise to at least 1.023-1.024
Look at your PH - ammonia and nitrate levels and if youre using API test kits, you may be getting false readings on water quality which may endure spikes.
Do also note that PraziPro will reduce oxygen and appetite of fish