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Not an emergency - keep an eye on it

Gills curled or clamped, but ammonia and nitrite both read zero

This looks like: strong water flow stress, or low dissolved oxygen — not a toxin problem

Do this firstCheck your filter's output — axolotls generally do best with gentle, baffled flow rather than a direct current across the tank. Redirect the outlet toward the glass or add a baffle if it's blasting straight across.

Why this happens

With ammonia and nitrite ruled out, the two next-most-common causes of gill changes are current that's too strong for an axolotl's slow-moving, low-flow preference, or low oxygen levels (more likely in warm water, since warm water holds less dissolved oxygen).

How sure are we? This is the right next step once toxins are ruled out by testing, but it's worth rechecking temperature at the same time, since heat and oxygen are directly linked.

What to do right now

  1. Check your filter's output — axolotls generally do best with gentle, baffled flow rather than a direct current across the tank. Redirect the outlet toward the glass or add a baffle if it's blasting straight across.
  2. Check the temperature — if it's crept above the safe range, dissolved oxygen drops at the same time gill stress rises, compounding the problem.
  3. Add extra surface agitation (an air stone, or angling the filter return toward the surface) to boost oxygen without adding direct current at axolotl level.
  4. Watch for a few days after adjusting flow — gill posture should visibly relax once the current is more comfortable.

What not to do

Stop it happening again

Set up gentle, baffled flow from the start and keep temperature in range - both are one-time setup decisions that prevent ongoing gill stress.

If that doesn't fix it

If gills stay curled after adjusting flow and confirming a safe temperature, retest ammonia and nitrite again — levels can shift between checks, and it's worth ruling toxins back in before looking elsewhere.

Catch this earlier next time — log your axolotl's water parameters in App-aquatic. Free forever.

← Back to Axolotl SOS diagnostic

This isn't veterinary advice - it's a directional read to help you decide your next step, based on the most common causes and independently checked sources (Merck Veterinary Manual, PetMD, established amphibian husbandry references). We can't see your axolotl, so pair it with a liquid test kit and clear photos, and see an exotic or aquatic vet for anything serious or not improving.