Why Are My Cherry Shrimp Swimming Around the Tank?

Red Cherry shrimp swimming to moss

Have you noticed your shrimp suddenly swimming around non-stop in their tank? There are a few reasons this could be happening and some of them are perfectly fine and healthy.

You should try and find the root cause before you try to “fix” anything with the setup.

The main key reasons for shrimp swimming around a lot are:

  • New shrimp exploring their surroundings
  • Bad water parameters causing stress
  • Temperature causing stress
  • Mating behaviour
  • Scavenging for food
  • Shrimp being stuck in a molt

New shrimp

If you've only just added the shrimp into a new tank, it's perfectly normal for them to either start exploring the tank or to hide.

Typically, most shrimp will immediately try to seek protection, climbing into small gaps and hiding amongst plants until they feel more comfortable.

The braver shrimp will begin exploring their surroundings trying to find out where the nearest food sources are, potential hiding spots for later, etc. These shrimp can be quite energetic, rushing around the tank at high speed, only stopping for a couple of seconds every so often.

As long as it's only a few shrimp looking busy, this is likely normal behaviour. However, if it's all the new shrimp then they might just be stressed from the move. Ensure your tank is fully cycled and drip acclimate new shrimp to reduce stress and help them adjust safely.

Bad water parameters

If you've performed a water change recently, it's possible that the new water is stressing them somehow.

  • Is it tap water? Has it been dechlorinated properly?
  • Have you changed more than 20% of the water?
  • Did you drip acclimate the new water back into the tank?

It's important to keep the shrimp tank's water parameters as stable as possible to avoid causing them any unnecessary stress or other health issues. Adding water back into the tank should be done slowly like with drip acclimation to reduce any parameter swings.

Make sure that water changes are done with water parameters similar to what's already in the tank.

Check your core water parameters:

Uncycled tank

Has the aquarium been fully cycled? If this is happening with a new tank you should test the water for ammonia ASAP.

Aquarium test kit result for ammonia

If you get a reading higher than 0 ppm of ammonia then this is likely the cause of stress. You should fix this issue immediately as ammonia is highly toxic to shrimp.

You should only add shrimp into a tank that's been fully cycled, and preferably matured for a few weeks too to grow biofilm and algae.

Other contaminants

If your water hasn't changed recently and all the parameters are within the healthy ranges, it's possible some other contaminant might have gotten into the water.

Some example ways this could have happened include:

  • Have you put your hand into the water after using hand sanitizer?
  • Has air freshener been sprayed nearby?

Mating behaviour

Try to identify the sex of the swimming shrimp, are they all males?

Roughly once a month each female shrimp will molt and release a pheromone into the water to get the attention of the males. This is when the female is ready for mating so the males will swim around excitedly trying to find her.

The female can be quite selective and play hard-to get by hiding in a spot for a while. As soon as she gets found she will often run off and try to find somewhere else to hide.

So if it looks like it's only male shrimp swimming around and searching over all the hardscape, it's likely completely natural behaviour and nothing to worry about.

Feeding

This sounds obvious but if you've recently added a powdered food into the tank, you'll likely have a tornado of shrimp as they try to find and eat it all.

This is especially true if your tank has high flow from your filter, it'll be spread all throughout the tank and get everyone hunting for it.

Temperature

A high temperature can cause stress on the shrimp just like any other water parameter.

The temperature of the water also affects how much oxygen it can hold, its pH level, the toxicity of ammonia, etc.

If you're near or over the high end of the safe temperature range for your shrimp, look into trying to cool the water down or simply turning down your heater if you have one.

Stuck in a molt

Unfortunately, if there's only a single shrimp darting around the tank in all directions it could be struggling to molt.

When a shrimp molts they split their old exoskeleton behind the back of their head first. They then bend themselves slightly and try to jump out the back of their old shell. When this goes wrong, the shrimp can get stuck inside their exoskeleton causing them to try and escape in a panic.

Common signs that they're stuck with a bad molt is seeing them laying on their side, and darting backwards constantly.

Unfortunately there's not much that can be done to help a failed molt except to prevent it happening in the future. Ensure that your water parameters are in healthy ranges, specifically the GH, KH, and TDS. This will make sure the water has all of the required minerals to promote healthy shell growth.