Thawing the right way
Frozen foods are only as safe as their handling, and the thaw is where most mistakes happen. Snap or cut off the portion you need while it is still frozen, drop it into a small cup of water taken from the tank, and let it thaw for a few minutes until the worms separate or the shrimp loosen. Tank water keeps the temperature and chemistry familiar to the fish. Never thaw under hot tap water, which cooks the food unevenly and washes in whatever the tap carries, and never microwave it. Once thawed, the clock is running: use the portion within that feeding, keep leftovers out of the tank, and never put thawed food back in the freezer, because thaw-and-refreeze cycles are where frozen food turns from treat to trouble.
Rinsing, and the salt question
Bloodworms can go in as they thaw, strained from their cup water, which is often pink with juices the tank does not need. Brine shrimp deserve an extra step: they are raised and packed in salty water, so tip the thawed shrimp into a fine mesh net and rinse them briefly under dechlorinated water or tank water before feeding. In a marine tank that rinse matters less; in a freshwater community tank it keeps a small pulse of salt and packing liquid out with every treat. Either way, pour the thawing water down the sink, not into the aquarium: the fish want the food, not the soup it arrived in.
Feeding amounts and leftovers
Frozen foods are rich, and fish will gorge on bloodworms long past the point of benefit, so offer a little at a time and watch it disappear. A portion that is cleared within a couple of minutes is about right; worms drifting down uneaten or shrimp settling into the plants mean the portion was too big. Uneaten bloodworms decay quickly in the substrate and are a classic cause of the cloudy water that appears the day after a treat. Siphon up leftovers rather than leaving them for the bottom feeders, since a cory will find a few, not a feast's worth. Treat frozen foods as the enrichment course around a good staple, a few times a week, and they stay a benefit instead of a burden on the filter.
Hands, hygiene and storage
Treat the freezer packs like raw ingredients in your kitchen: wash your hands after handling them, keep them sealed and properly frozen between uses, and discard packs that have thawed and refrozen in a warm shopping bag on the way home, because the risk is not worth the saving. Some keepers find bloodworms irritate their skin, so serving with tweezers or a pipette is a sensible habit rather than bare fingers. Writing the whole sequence, thaw in tank water, rinse the shrimp, feed small, remove leftovers, into the routine in KinsLe Care Teams keeps every person who feeds the tank handling frozen foods with the same care, so treat night stays safe no matter who is holding the cup.