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How Your Fish Disappeared From Its Tank!

We know that it may sound strange but the number of people that we see reaching out due to having had a fish disappear from its tank is constantly increasing and although it may be surprising to some people, it is common for a fish to just disappear from an aquarium.

Due to it being so common to lose a fish as well as seeing so many people reaching out and asking about their fish disappearing, we decided to publish this article on the topic.

Our hope is that we will be able to help our readers better understand what’s actually happening to their fish that seem to disappear.

There are countless reports from people in the fish keeping hobby each month about their fish disappearing with many of them having a pretty unique way of vanishing from their tank.

Unfortunately, in some cases, you can be very careful to try and reduce the chances of anything like this happening with you fish and it may still end up disappearing.

It’s just one of those things that you have to factor in as a potential risk, especially with certain fish species or fish that are in overstocked tanks or tanks that are too small for them.

Can A Fish Disappear In A Fish Tank?

Fish can disappear from their fish tank and it is, unfortunately, more common than most people who are new to fish keeping initially realize.

The vast majority of the time when fish disappears it means that the fish has been eaten by a tank mate or has somehow ended up meeting its maker in some other way but there are a small number of reports of fish who were simply hiding very well and then deciding to reveal themselves.

We have even seen reports of some of the smaller fish species who have taken to living inside holes in the rocks in their tank rather than swimming around like the other fish making it hard to find the fish due to some of the holes in the rocks being deep.

This is often due to the fish being bullied by its tank mates constantly and its only way to feel safe being to hide in any safe area it is able to find.

Some fish do require a large number of hideouts or thick live plants in their tank so at first glance it may seem as though a fish has disappeared when in fact it’s just relaxing in a hideout.

Some people also keep a large number of fast moving schooling fish who rapidly swim around making it hard to count them with some people miscounting multiple times and thinking one of their fish has disappeared when in actual fact, it’s been in the tank all alone and they have just miscounted.

How Your Fish Disappeared From Its Tank!

The three most common reasons a fish may disappear from its tank is due to being eaten by its tank mates, it jumping out of the tank and ending up down the back of your aquarium stand, and being able to get itself into a fish hideout but being too big to get itself out.

There are a number of other less common causes too with some disappeared fish having been sucked into the tank filter if it has incorrect flow settings.

Many people new to fish keeping simply fail to realize just how common it is for a fish to jump out of its tank too!

With many beginners to the hobby accidentally putting fish in tanks that are too small for them, the chances of a fish jumping out the first chance it gets are increased further too but it can be common for many species of fish to just randomly jump out of their tank even if it has plenty of space.

A large number of people will also accidentally stock unsuitable fish in the same tank as each other with one species usually ending up being a food source for another.

We have also seen people adding fish to tanks that they keep axolotls or crabs in and failing to realize that they will eat the majority of fish you put in their tank with them.

Do Fish Hide When They Are Dying?

Certain fish species will hide when they are dying with some fish being very creative in their hiding spots making it difficult to find them giving the impression that they have disappeared.

If the fish dies in a creative hiding spot and you have shrimp and snails in your tank, it really won’t take long for the fish to be eaten.

Depending on the species of fish as well as the tank mates it has, they may even be able to eat the bones of the fish too leaving little to no remains at all.

People often overlook the fact that snails will eat bone as a way to increase the calcium in their diet to help them maintain a healthy shell.

This is why there are so many people convicted that their fish literally disappeared when in actual fact, it died and was eaten by its tank mates with no trace of the fish being left behind.

Crabs are becoming more and more popular in tanks too and it is very popular for crabs to do similar things in certain situations as their shells require a large amount of calcium to maintain.


That brings our article going over why fish commonly disappear from their tanks to an end. There are a number of common causes ranging from the fish hiding to it jumping out of the aquarium to it being eaten by its tank mates that can create the illusion that the fish disappeared. Most of the time, over the span of a month or two, most people do end up discovering what happened to either fish either due to the smell or a spike in nitrate levels in their tank.