White spots like salt or sugar
This looks like: ich (Ichthyophthirius multifiliis) — a parasite with a temperature-dependent life cycle
Why this happens
White trophonts lodge in skin. Medic only hits theronts swimming — that is why treatment duration matters and why raising temp alone is a strategy for tolerant species, not magic solo.
What to do right now
- Confirm species med tolerance — scaleless = careful dosing.
- Remove carbon during treatment windows if label says.
- Increase aeration — warm water holds less oxygen when you raise heat.
- Vacuum bottom to drop parasite load resting in detritus.
- Finish the full label course — quitting early retrains superbugs.
What not to do
- Don’t confuse ich with micro bubbles stuck from injury healing.
Stop it happening again
Quarantine new fish for two to three weeks, avoid chilling the tank, and keep stress low - ich almost always hitchhikes in on new arrivals.
If that doesn’t fix it
Dust all over skin → consider velvet diagnosis path.
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.