Help Needed: Flowerhorn with Partially Open Mouth, Swollen Stomach, and Shrunken Kok

[All Sev]

Hi everyone,

I’m seeking advice on a flowerhorn I’ve been observing. This fish was bought by a friend around 3 months ago. I saw an old video from 2 months back where the fish already had a partially open mouth, and now it’s still the same — the mouth doesn’t fully close, but the fish is eating and active.

Now, I’ve noticed additional issues:

• A slightly swollen stomach (not pineconed, but looks distended — circled in image).
• A shrinking or undeveloped kok.
• When the fish opens its mouth, there seems to be something visible inside, like tissue or a mass — not sure if it’s abnormal or just gill structure.

The fish is housed alone, active, and eats, but something seems off.

• I’ve attached photos showing the jaw, stomach swelling, and head for reference.

What I Want to Know:

• Is this partially open mouth due to an deformity, or something inside the mouth or bacterial infection?
• Could the stomach swelling be internal infection, bloat, or tumor?
• Is the shrinking kok a sign of stress, poor nutrition, or illness?
• Any ideas on what that structure inside the mouth could be?

Would appreciate any advice or similar experiences from fellow FH keepers. Thanks in advance!

kno4te
Magnus_Bane
Deadeye
RD.
@hyb

 

[kno4te]

Sorry for the late reply. Hard to make out what’s going on. Could be water quality issues to bad genetics since the fish is captive bred. How long have you had the fish? What’s you water change schedule? Wate parameters? What are you feeding?