6 Signs That Your Fish is Happy in a New Tank

When you buy a new fish or get a new tank for existing fish, the transfer process can be quite tricky. After all, fish are quite sensitive.

Whether tankmates, tank size, water temperature, pH, food, or filtration, many factors determine whether or not your fish will be happy and healthy.

Now, of course, fish aren’t like humans, or even like dogs or cats, but how to tell if fish are happy in a new tank. Let’s find out.

There are 6 main ways to tell whether a fish is happy in its tank, so let’s take a quick look at each of these 6 factors or signs.

1. Bright Colors

One sign that your fish is happy and healthy is if it is brightly colored. Some fish aren’t brightly colored, to begin with, but even with these, you can often notice color changes, or at least in how solid those colors are.

For example, a goldfish should have a really bright orange color. However, if your goldfish’s color is fading, turning whiter and paler, it is a sign of unhappiness and unhealthiness.

If your deep blue fish is a pale blue all of a sudden, you have got a problem.

2. They Interact With Others

Another sign that your fish is happy and healthy is they are interacting with other fish and tankmates. People with little fish keeping experience will often put many fish into the same tank without checking to see if they are compatible.

If fish are not compatible, one may end up bullying, picking on, and stressing other fish, which can eventually lead to death.

If your fish are all compatible, which makes them happy, they will interact with each other. However, if you notice your fish hiding in corners or avoiding the other fish, it’s probably not too happy.

3. They are Breathing Properly

Another sign that your fish is happy and healthy it is if it is breathing properly, with a relatively slow and steady contraction of the gills.

If your fish is breathing very slowly or very rapidly, if it comes to the surface to gulp for air, or if it displays other odd behaviors—these are signs that your fish is unhappy or unhealthy or both.

More often than not, this has to do with health rather than happiness. Yet, there are cases where stress can cause breathing issues in fish, almost like when stress makes us humans hyperventilate.

4. Healthy Looking Fins

The next sign is if the fins look healthy. Often, fish that are unhealthy and stressed will have ragged and ripped fins.

This could be caused by another fish nipping at the fins or caused by a litany of diseases. Either way, if your fish has solid fins that are not tattered, likely, happy, and healthy.

If you see that your fish has spots on its fins or ragged fins, you need to take immediate action to remedy the situation.

5. A Good Appetite

Another sign is if it has a good appetite. If your fish are not eating well, chances are that they are unhappy, unhealthy, and probably both.

Your fish may be too stressed to eat, which happens more than you might think; this stress can be caused by many factors.

You might have fish competing for food in the same tank, which may lead to some fish not getting the nutrition they need, another thing that will cause unhappiness.

Moreover, some fish can be picky eaters. If you don’t have the right kinds of foods for your specific fish or have food that your fish doesn’t like, it obviously won’t be too happy.

Not eating is always a bad sign, and this is the case with fish, humans, and other animals alike.

6. Actively Swimming

A positive sign that your fish is happy is if it is actively swimming around in the tank. You will have to use common sense here, as some fish are naturally more active than others.

In general, sitting in the same spot or even hiding are both ominous signs. If your fish is actively swimming around, it’s probably doing just fine.


Those are the 6 most significant signs that indicate whether your fish is happy and healthy.

If you notice any issues, seeing as fish are quite fragile, it is imperative to tackle those issues immediately.