How Many Cherry Shrimp per Gallon? Stocking Guide by Tank Size
How many cherry shrimp can you keep per gallon? A simple stocking guide for 2.5 to 20 gallon tanks, how many to start with and when a colony gets too big.
Photo: TonyZimbinski, CC BY-SA 4.0In this guide
Short answer: a common rule of thumb is up to 10 cherry shrimp per gallon (about 2–3 per liter) in an established tank. For a new tank, start well below that: 10–20 shrimp in a 5–10 gallon tank is a good start. The colony will breed and fill the space by itself.
Why shrimp can be kept so densely
Cherry shrimp (Neocaridina davidi) grow to about 2–3 cm and produce very little waste compared with fish. The real limits are:
- Water quality. More shrimp and more food mean more waste. A small tank with lots of shrimp and heavy feeding goes wrong fast.
- Food. Shrimp graze on biofilm and algae all day. A tank with many plants and surfaces supports more shrimp than a bare one.
- Stability. Bigger volumes change more slowly. That matters more to shrimp than how many shrimp are in there.
Stocking by tank size
| Tank size | Shrimp to start with | Comfortable colony size |
|---|---|---|
| 2.5 gal (10 L) | 5–10 | Up to about 25 |
| 5 gal (19 L) | 10–15 | 30–50 |
| 10 gal (38 L) | 15–20 | 60–100 |
| 20 gal (75 L) | 20–30 | 150+ |
These are guidelines, not hard limits. A mature, planted tank with good filtration can hold more; a new or bare tank should hold fewer.
How many to buy at the start
Buy at least 10, ideally 15–20. There are three reasons:
- Breeding. You need both males and females. With 10 or more, you’re very likely to get both.
- Confidence. Shrimp in a larger group come out and graze in the open more often.
- Losses. A few shrimp may die in the first weeks after a move. A larger group absorbs that.
Only add shrimp to a fully cycled tank.
Signs the colony is too big
A healthy colony grows quickly, and a 5 gallon tank can go from 15 to over 100 shrimp in a year. Watch for:
- Nitrate rising faster than usual between water changes
- Shrimp swarming food within seconds and nothing left to graze
- Fewer babies surviving to adult size
- Glass and plants picked completely clean
When this happens, sell or give away some shrimp, move some to a second tank, or feed a little less and do water changes more often.
Shrimp with fish
Most fish will eat baby shrimp, and many will eat adults. If you want a colony to grow, keep shrimp alone or with snails. If you do add fish, plan for fewer shrimp surviving and add dense plants or moss where babies can hide.
Frequently asked questions
Can I keep one cherry shrimp alone?
It will survive, but shrimp aren’t meant to be kept alone and you won’t see natural behavior or breeding. Keep a group of at least 10.
How many cherry shrimp in a 10 gallon tank?
Start with 15–20. A mature 10 gallon tank can comfortably hold 60–100 adults.
How fast will my shrimp colony grow?
A female carries 20–30 eggs about every month or so in good conditions. Most colonies double within a few months once they settle in. Read more in our cherry shrimp breeding guide.
