Count Heads First, Because a Guppy Tank Changes While You Are Away
The first check for a returning guppy keeper is a census, not a water change. Guppies breed readily, so a heavily pregnant female who looked ready before you left may have filled the plant thickets with fry during your holiday, and the colony you feed tonight may be larger than the one you left. Count the adults methodically, corner by corner, then part the floating plants gently and look for fry hovering near the surface. A missing adult matters in a guppy tank because a small body decaying behind a filter intake can foul a modest volume of water quickly, so account for everyone before you do anything else.
Check the Heater and Test the Water
Guppies depend on steady warmth, so confirm the heater light cycles and the thermometer reads what the tank is normally kept at, since a heater that failed on day two explains almost any odd behaviour you are about to see. Test for ammonia and nitrite next, and look at the surface for the dull film that builds when flakes land twice a day and half of them rot where they fall. Check the filter intake sponge for a mat of trapped food, and clear it if the flow has slowed to a trickle. Guppy tanks are often small, and small volumes swing faster, so a week of small overfeeds shows up sooner here than in a big aquarium.
Read Colour, Shape and Behaviour Fish by Fish
Male guppies advertise their condition in colour, so a male who was vivid before the holiday and now looks washed out, with fins clamped close to his body, has had a harder week than his tank mates. Watch the females for a sunken belly behind the dark gravid area, which can follow a recent drop of fry combined with missed meals, and for any fish scratching against leaves or wood. Fry should hold station in the plants with quick, darting movements; fry lying on the substrate or gasping at the surface point back to the water, not to the babies themselves. Note which fish look thin, because in a busy guppy colony the shyest feeders lose ground fastest when a sitter scatters food and walks away.
Feed Small and Give the Colony a Day to Settle
Offer one small pinch of crushed food spread across the surface so fry, females and slower males all reach some, then watch the whole feeding rather than topping up whoever begs at the glass. A guppy that has eaten will show a gently rounded belly; keep feeding light until you see that shape return at normal portions. If fry numbers have jumped, decide calmly whether your plants and filter can support the larger colony rather than making changes on your first tired evening home. Write down the sitter's account of any births, losses or equipment oddities before the details blur.
When a Guppy Return Check Turns Serious
Several guppies gasping together, a whole group hanging at the surface, or deaths on consecutive days after your return call for prompt advice from an aquatic veterinarian or a trusted local fish specialist, along with an immediate partial water change while you seek it. A single fish with a bent spine, wasting body or persistent hiding deserves separation and watching rather than being left to compete. Passing on the colony's recent history helps whoever advises you, and keeping that history in your KinsLe Care Pass — fry counts, heater notes and sitter observations — means the next holiday handover describes the guppy colony as it actually is.