The guppy's particular problem with fireworks
A guppy's whole life happens in the top half of the tank, close to the light, close to the surface, and — when something startles it — briefly out of the water altogether. Guppies are enthusiastic, accurate jumpers, and a night of random flashes gives them a reason to jump every few minutes. That, more than fear itself, is the fireworks risk for this species: not a stressed fish in the tank, but a dried one behind it. The second consideration is who shares the tank. A guppy setup usually holds a mixed little society — males with long, draggy tails who tire fast and tear fins in a scramble, females heavy with fry who can do without a night of being chased around by panic, and fry themselves, whose whole survival plan is the plant thicket. Fireworks care for guppies is therefore mostly mechanical: keep everyone in, keep the cover intact, and let small fish be boring for one evening.
The afternoon: lid, gaps, and cover
Work from the top down. Seat the lid or hood properly and then hunt for the gaps — around the filter body, where cables exit, along a warped back edge — and cover each with a strip of mesh, a piece of filter sponge, or a folded cloth just for the night. Guppies need a surprisingly small slot, and the gap you have ignored for months is the one that matters tonight. Lower the flash contrast by planning a low lamp on in the room from dusk, so the tank never sits in full darkness waiting for the next strobe. Then check the furniture of the tank at guppy scale: the plant thickets, floating cover, and corners where fry and resting females sit should be dense and undisturbed, and this is not the day to trim them back. Feed the tank in the afternoon, a normal amount, and let that be the last event of the guppies' day.
During the display: small fish, hands off
Once the noise starts, the guppy tank asks for the least of any tank in the house. No lid-lifting to count heads — a lifted lid during a flash sequence is an open door at the worst moment — and no net rescue missions for a fish that is merely hiding; a guppy deep in the plants with its color slightly down is coping, not failing. If your strain's males have very long tails, watch from outside the glass for one genuinely stuck or trapped rather than merely resting, and intervene only for that. Room noise near the tank matters less to guppies than light does, but a subwoofer against the stand's wall will still send the school scattering, so keep the party's hardware a wall away. A towel draped over the front glass of a small guppy tank, top edge open for air, is a perfectly good blackout curtain for the worst half-hour.
Morning: count, color, and breakfast
Guppies announce their state quickly in the morning. Males color up and resume displaying within the hour if the night cost them little; a tank that stays dull, clamped, and plant-bound into midday had a harder night and earns a partial water change and a quiet day. Count heads at feeding, when everyone must come out — that is when a missing jumper reveals itself, and a quick look behind and beside the stand is worth doing before concluding anything. Check long tails for fresh splits and heavily pregnant females for early, scattered fry, a known response to a stressful night, and simply make sure the plant cover is dense enough to hide them. Anything unusual at breakfast is worth a brief written note before the day moves on. Put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.