Invert Food
The most common mistake with shrimp and snails is assuming they live on algae. They do not, quite — and an invertebrate colony that stops growing is usually underfed rather than unhappy.
Biofilm first, food second
What shrimp actually graze all day is biofilm, the invisible microbial layer on every surface in a mature tank. A brand-new tank has almost none, which is why shrimp added too early struggle even when the parameters read perfectly. Give a tank a few weeks, or add botanicals and leaf litter, before the colony goes in.
Feed small, and remove what is left
A pinch every two or three days is plenty for a typical colony, and uneaten invertebrate food fouls water quickly because it is protein-dense. Feed on a dish if you can — it keeps the food off the substrate and lets you see exactly what was not eaten, which is the fastest way to calibrate the amount.
Calcium and minerals matter here
Shrimp moult, and snails build shell — both need minerals in the water, not just in the food. A failed moult is a common cause of sudden loss in an otherwise healthy-looking colony. Our hard San Diego tap water is genuinely an advantage for Neocaridina and snails. Caridina keepers working from RO water have to remineralise deliberately, and that is where a mineral supplement stops being optional.
Check the label for copper
It bears repeating on every invertebrate page: copper is lethal to shrimp and snails at doses fish barely notice, and it turns up in foods and supplements as well as medications.
See also shrimp, snails and invertebrate supplements.