Invertebrate feeding

Shrimp, snails, and crayfish play different roles in the aquarium. Most graze biofilm and detritus rather than competing for flake at the surface. The right food supports molting, shell health, and breeding — overfeeding inverts is a common cause of planaria, detritus worms, and algae spikes.

Neocaridina (cherry shrimp)

Primary diet: Biofilm on plants, wood, and glass — a mature tank feeds them passively
Supplement: Shrimp-specific pellets, blanched veg (zucchini, spinach), occasional frozen food
Frequency: 2–3 small feedings weekly in established tanks; daily only in new or heavily stocked tanks
Water: Stable parameters matter more than food variety — see GH & KH

Caridina (bee / tiger shrimp)

More sensitive to TDS and mineral content than Neocaridina
Use species-specific remineralisers — see RO & remineralisation
Feed sparingly; uneaten food crashes parameters quickly in small volumes
Biofilm from cholla wood and alder cones supports grazing

Snails

Species	Diet notes
Nerite	Algae grazer; supplement algae wafers if tank is clean
Mystery / apple	Algae + blanched veg; avoid copper in any medication
Ramshorn / bladder	Detritus and leftover food — population explosion = overfeeding signal
Assassin	Other snails; occasional protein

Calcium: Snails need calcium for shell repair. Cuttlebone, crushed coral in filter (if pH allows), or calcium-rich foods support shell health.

Crayfish & crabs

Omnivorous scavengers — protein-heavy but need vegetable matter
Sinking pellets, frozen shrimp, and blanched veg
Remove uneaten food within an hour — ammonia spikes in invert-only tanks
Molting: Provide hiding places; do not disturb during molt; iodine supplements are debated — stable water matters most

Foods to avoid

Copper-based medications — lethal to shrimp and snails
Large quantities of protein in shrimp-only tanks — fouls water fast
Overfeeding to "help" algae eaters — excess food causes more algae, not less
Human foods with salt, oil, or seasoning

Feeding technique

Feed after lights out or in a quiet corner so fish do not steal invert food
Use feeding dishes for shrimp pellets — easy to remove leftovers
Blanch vegetables 1–2 minutes; cool before adding
One pea-sized portion per 10 shrimp is a rough starting point

Signs of feeding problems

Failed molts (white ring of death) — often GH/KH or diet imbalance
Snail shell erosion — low calcium or acidic water
Planaria explosion — overfeeding; reduce food and consider manual removal
Shrimp hiding constantly — check ammonia, nitrite, and copper exposure first

Frequently asked questions

Do shrimp need feeding if the tank already has biofilm and algae?

A mature, lightly stocked tank often sustains a small colony with no supplementary feeding at all. Larger colonies need topping up, but underfeeding is far safer than overfeeding: shrimp are small, and uneaten food fouls water quickly in the volumes they live in.

Why do my snail shells look pitted or eroded?

Almost always insufficient calcium or a low pH dissolving the shell faster than it can be laid down. Check GH and KH — see RO water and remineralisation — and offer a calcium source such as cuttlebone or a mineral supplement.

Can invertebrates just eat the fish food?

They will, but it is rarely a complete diet. Shrimp need more plant matter and biofilm than most fish foods provide, and copper — present in some fish foods and most fish medications — is toxic to invertebrates. Check labels before dosing anything into a shrimp tank.