Here’s the scenario. You look in your tank and find that one of your fish is dead. But is it dead or is it sleeping? How do you tell if a fish is dead? And how do you dispose of a dead fish? 

Aquatic shop workers are constantly told by their customers that one of their fish is dead when most of the time it’s just a catfish doing what catfish do - sitting motionless on the bottom of the tank.

And did you know that Clown loach are so-called because of their clowning around which includes lying on their sides and looking dead? But if it’s not those two things here’s how you check.

Check its breathing

Watch the fish for a couple of minutes and see if its gills move. Even if they only move every 10 seconds or so the fish is still alive. 

Watch its eyes

The eyes are a dead giveaway. If you take the fish out of the water and lie it on its side, the eyes of a dead fish will not move and stare motionless like fish at the fishmongers. If the fish is still alive the fish’s pupil will rotate downwards as the fish tries to right itself. 

Feel the body

Is the body soft and flexible or is it hard and stiff? If it's stiff, Rigor Mortis has set in and the fish is dead. If it’s still floppy the fish may still be alive or has died very recently. 

Smell it

Does it smell fishy or does it smell like bin juice? If it stinks and makes you gag, it’s 100% dead and decomposing. 

Is it floating or sinking?

Not all dead fish float and floating can depend on the decomposition process. Small fish like tetras and guppy corpses tend to float whereas catfish and cichlids tend to sink. A pond fish may sink first then float later as gases build up in the body, and that’s when you’ll spot it. 

Is it dead or sleeping?

Fish can sleep but they don’t have eyelids so they should just look awake at all times. Most fish “sleep” in midwater, which they do the right way up and just hover in the current. Only loaches and catfish would sleep on their sides or even upside down if they stuff themselves into a cave. If a barb, goldfish, angelfish or most other popular midwater fish are on their sides on the bottom they’re not sleeping. They’re sick. 

How do you dispose of a dead fish? 

Don’t flush it down the toilet as toilets aren’t meant for fish disposal and if you block a drain down the road you’ll look stupid when the drain people pull out one of your fish. Especially if your tank is visible through the curtains! Tie it up in a bin bag and place it in the waste.

You can bury fish in the garden although make sure you bury it deep enough to stop foxes digging it up, or cats. If your local fish store has asked to see the corpse keep it in the freezer as dead fish rot and smell very quickly. 

Test your water

The number one killer of aquarium fish is poor water quality. If any of your fish look dead, dying or unhealthy check the water parameters with a test kit.