Freshwater clean-up crew

A freshwater clean-up crew works through algae, leftover food and detritus: nerite and mystery snails on the glass, shrimp in the moss, crabs and crayfish picking over the substrate. They help with maintenance but never replace it. Profiles list tank size and care for each species.

Tank size: 5–53 gal; 5 gal (19 L) to 53 gal (200 L); half the list needs 10 gal (38 L) or more
Temperature: 72–82°F; 22–28°C, most of the list
pH: 6.8–8.0; Most of the list
Difficulty: 46 easy; 51 medium · 5 difficult
Temperament: 61 peaceful; 34 mostly peaceful · 7 aggressive

99 species and 17 varieties

Start here

The crew for a first tank

The zebra nerite is the freshwater algae snail, 1 inch (2.5 cm), marked beginner, and it cannot breed in freshwater, so the count stays put. The Amano shrimp is the best algae shrimp there is, 2 inches (5 cm) for 8 gallons (30 liters), marked beginner. The mystery snail is marked easy at 2 inches (5 cm) and eats leftovers and dead leaves without touching live plants. The cherry shrimp works biofilm in the moss at 1.6 inches (4 cm) for 5 gallons (19 liters). The Malaysian trumpet snail lives in the substrate and turns it over at night. The red ramshorn snail cleans leaves and glass and breeds to match the food.

The rule

What a clean-up crew does and does not do

A crew eats algae, leftover food and dead leaves. It does not remove waste, it adds to it, so the water changes stay exactly where they were. It needs feeding once the glass is clean: algae wafers and blanched vegetables, or the snails starve and the shrimp thin out. The snails need calcium and a pH above 7 for their shells, and every animal here dies from copper, so the medications and fertilizers get their labels read. And the crew has to match the fish: a shrimp is food to any fish with a mouth that fits it.

01
Algae, not waste
The water changes stay
02
Feed them
Wafers and blanched veg once the glass is clean
03
Calcium and no copper
Shells need one, everything here dies from the other
04
Match the fish
A shrimp is food to any mouth it fits

Shrimp

Ghost, bamboo and the cherry colors

The ghost shrimp is the cheap scavenger, marked easy at 1.6 inches (4 cm), and it will grab a fry. The bamboo shrimp filters the water with four fans at 3.9 inches (10 cm) for 13 gallons (50 liters), a specialist rather than a cleaner. The tiger shrimp grazes like a cherry in cooler water at 64–73°F (18–23°C). The blue dream and yellow shrimp are the cherry shrimp in other colors, the same beginner rating and the same 5 gallon (19 liter) minimum. The Neocaridina shrimp is the wild form all of them came from, and the profile for it covers the whole species.

Snails

Nerites, an assassin and the cool-water snails

The tiger nerite and the horned nerite are separate species that graze algae like the zebra nerite. Both want 72–79°F (22–26°C) and a pH of 7 or higher, and the horned nerite is marked easy. The assassin snail hunts other snails at 1 inch (2.5 cm), marked easy, and leaves plants alone. The gold rabbit snail grazes soft algae at 2.8 inches (7 cm) for 16 gallons (60 liters) in warm, hard water. The Japanese trapdoor snail is a cool-water snail, marked easy at 2 inches (5 cm) for 64–77°F (18–25°C). It suits an unheated tank or a pond. The great pond snail, the great ramshorn and the wandering snail also take cool water. The bladder snail arrives on plants, breeds to the food supply, and is a sign of overfeeding rather than a problem.

Crabs and crayfish

Dwarf crayfish, small crabs and the big ones to skip

The Thai micro crab is 1 inch (2.5 cm), fully aquatic and marked peaceful, a filter feeder for a 5 gallon (19 liter) tank. The pom pom crab is another fully aquatic crab, marked easy at 1.6 inches (4 cm). The vampire crabs are not: the purple vampire crab lives mostly on land and wants a paludarium, 1 inch (2.5 cm) for 10 gallons (38 liters). The orange dwarf crayfish is 2 inches (5 cm) for 10 gallons (38 liters), marked easy and mostly peaceful, and picks over the substrate without wrecking the plants. The Cajun dwarf crayfish is the same at 1.6 inches (4 cm) for 5 gallons (20 liters). Both will grab a weak or molting shrimp. The electric blue crayfish is 4.7 inches (12 cm), marked aggressive, and it eats plants and fish. The Louisiana and marbled crayfish are marked aggressive too. The Cherax crayfish, such as the zebra crayfish, eat snails and shrimp and catch sick, slow or bottom-resting fish. All of these larger crayfish stay out of a clean-up crew.

By the numbers

Smallest

Largest

Easiest to keep

Most peaceful

Fits a 30 gallon tank

FAQ

Common questions

What is the best algae eater for a freshwater tank?

An Amano shrimp and a nerite snail together. The Amano eats hair algae and the nerite cleans glass and rock. For algae-eating fish, the otocinclus and the bristlenose pleco have the algae eaters list.

Will a clean-up crew fix an algae problem?

No. It eats the symptom. Algae grows from light and nutrients, and the fix is fewer hours of light, fewer nutrients and more plants, with the crew keeping up afterwards.

Can crayfish live with fish?

The dwarf crayfish can, with fish that stay off the bottom. The electric blue, Louisiana and marbled crayfish are marked aggressive and catch sleeping fish, so they get a tank of their own. The Cherax crayfish are marked mostly peaceful. They catch sick, slow or bottom-resting fish, so keep them alone or only with fast fish that stay off the bottom.

Do freshwater crabs need land?

The vampire crabs, the red apple crab and the batik crab do, and drown without it. The panda crab and the tricolor Borneo crab need a paludarium that is mostly water with some land. The Thai micro crab, the pom pom crab and the Thai dwarf rock crab are among the crabs that need no land section.

How many shrimp should I start with?

Ten cherry shrimp in a 5 gallon (19 liter) tank. They breed to the food supply, and a colony of a hundred in a year is normal.

Why do my snails keep dying?

Soft or acidic water dissolving the shell, copper in a medication or fertilizer, or starvation once the glass is clean. Check the pH, read the labels and drop in a wafer.

Index