When guppies arrive (whether from a shop, a friend, or shipping), the first day matters. Many losses blamed on “shipping stress” are actually acclimation mistakes: temperature shock, rapid chemistry swings, or ammonia spikes from bag water being dumped into the tank. The good news is that acclimation is easy once you understand the failure points.
Mistake 1: temperature mismatch
Even a few degrees can stress fish badly. Float the bag long enough to match temperature before doing anything else.
Mistake 2: rushing chemistry changes
Going from one water source to another too fast can shock fish. Gentle mixing over 20–30 minutes is often enough for guppies without turning it into a long ordeal.
Mistake 3: pouring bag water into your tank
Bag water can contain built-up ammonia and waste. Net fish out and discard the bag water instead of introducing it into your tank.
Mistake 4: bright lights and heavy feeding
New fish settle better in low light. Offer a small meal only after they calm down, or wait until the next morning if they look stressed.
Mistake 5: changing your tank on arrival day
Don’t re-scape, deep clean, or do major changes right as fish arrive. Your job is to keep the environment predictable for the first few days.
Acclimation doesn’t need to be fancy. It needs to be calm and clean. If you avoid the common mistakes, most guppies settle quickly and start eating and colouring up fast.
