Slow losses when feeding isn’t crazy
This looks like: infectious disease, internal parasites, or poor individual fish quality
Why this happens
Not every death is your chemistry — columnaris, internal worms, and TB can kill over weeks. Pet-shop fish sometimes arrive compromised.
What to do right now
- Photograph skin, fins, and poop — clarity drives the next move more than guesswork.
- Isolate one struggling fish if you can with mature filter fiber and matching temp.
- Test GH/KH if you never have — some species crash on ultra-soft water slowly.
- Pause new purchases; ask the store about recent shipment stress.
- Research symptoms on our species pages before buying meds (ich vs fungus look different).
What not to do
- Don’t shotgun five medications — identify first when possible.
Stop it happening again
Quarantine new fish, buy from shops with healthy stock, and keep parameters stable - a strong tank shrugs off bugs that a stressed one cannot.
If that doesn’t fix it
If bodies show ulcers or fray threads together, see bacterial columnaris patterns.
Catch this earlier next time — log your water parameters in App-aquatic. Free forever.
This isn't veterinary advice - it's a directional read to help you decide your next step, based on the most common causes. We can't see your fish, so pair it with a liquid test kit and clear photos, and see an aquatic vet or a trusted local fish shop for a valuable or seriously ill fish.