- Sandfish is eating less than usual or not eating at all
- Breeding season (males only, June-July)
- Brumation (November-February)
- Low temperatures
- Parasite infestation
- Side effect of antibiotic or deworming treatment
When not related to breeding season or brumation, loss of appetite usually indicates either a serious issue with husbandry or serious illness. Reevaluate your enclosure, and if you can’t find anything wrong there, make an appointment with a certified reptile veterinarian, especially if the sandfish has begun losing weight.