Clutchmates Are Your Built-In Comparison
Failure-to-thrive rarely announces itself in a single dramatic sign; it shows as a gap opening between siblings raised in identical conditions. The hatchling that concerns you will be the one still looking freshly hatched while clutchmates fill out, the one found in the same hiding spot at every check while others rotate around the enclosure, and the one whose feeding ledge is consistently full in the morning while siblings have licked theirs clean.
Handle each baby briefly in turn. A thriving hatchling feels surprisingly solid for its size and grips with intent; a struggling one feels fragile, moves weakly and may sit limp rather than making the small jumps crested geckos are known for. Trust that contrast, because keeping siblings gives you a control group most keepers never have.
Weigh Weekly and Believe the Trend
Visual checks miss slow decline, so weigh every hatchling on the same gram scale, on the same day each week, and record the numbers in a row where divergence is impossible to ignore. Healthy crested gecko hatchlings gain slowly but steadily. A baby that holds the same weight for two weeks while clutchmates gain, or that loses any weight at all, has crossed from watch-and-wait into act-now.
Pair the weights with feeding notes: which nights the diet was eaten, whether live insects were offered and taken, and any shed dates. A hatchling eating enthusiastically but not gaining raises different veterinary questions, such as parasites, than one simply not eating, and the notes let a vet separate those paths quickly instead of starting from guesses.
Rule Out the Fixable Causes in Its Own Tub
Before assuming illness, audit this hatchling's micro-environment. Temperatures that run too warm suppress crested gecko appetite, and a tub placed higher on a rack or nearer a heat source can differ from its siblings' tubs by enough to matter. Check humidity cycles too: constant sogginess and constant dryness both stress a baby, while a daily misting that lets surfaces partly dry between sprays suits them better.
Competition is the other common cause if babies are housed together. A bolder clutchmate monopolizing the ledge or the best hide can quietly starve a shy sibling that eats fine alone. Move the falling-behind hatchling to its own small tub with its own ledge at an easy height, offer fresh diet nightly and tiny live insects for stimulation, and give it a week of uncontested feeding before concluding the problem is medical.
The Signs That Mean Vet Now, Not Next Week
Some findings skip the home-trial stage. Sunken eyes and wrinkled, tenting skin point to dehydration; a hatchling that cannot right itself, trembles, or has a soft, bendy jaw or limbs needs urgent assessment, as does one passing runny droppings, prolapsing, or refusing all food while continuing to lose weight after separation. Bring the weight log, feeding notes and a fresh dropping sample if you can collect one.
Early action is the whole advantage here, and KinsLe Pet Passport keeps this hatchling's weights, feeding notes and vet findings together in one packet so the divergence from its clutchmates is documented, not remembered.