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Top 5 reasons why your fish is not growing in aquarium

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Fish is not growing in the aquarium is not a very common problem but if you see that your fish is not growing then you may have some certain hidden issues.

Before fixing those issues you must identify these and from this article, you are going to know about those issues which prevent your fish’s growth.

Inappropriate fish tank size and lack of proper nutritious food are the main two reasons fishes are not growing in aquariums. But improper lights, bad water conditions, and frequent fluctuation of water temperature are the secondary causes of under-developed fish.

But I guess you want to know more about what’s wrong with your fish right?

So without wasting much time let’s dive deep into the topic

Inappropriate fish tank size


Tank size is the most important reason why your fish is not growing much right now. May your tank be over-crowded and all of your fish is not getting proper food due to this reason. You should know that every fish species needs some certain space to grow.

Now if you put fishes randomly in an aquarium just for visual satisfaction then it will not work that way. You must know the proper tank size needed for a particular fish species otherwise all of your fish species’ growth will be hampered.

Here I’ve given a chart which will give you an idea about the tank size of different types of fishes. So you should remember that more space means more chances to grow a fish. So try to build an aquarium with more space.

But if you don’t have money right now for bigger aquariums then you can start with the smaller one with some basic fishes like Guppy, Neon Tetra, Harlequin Rasbora, Molly fish, etc.

Lack of nutritious Food


Proper food makes your fish healthy and helps to grow faster. If you want to see your fish is growing then you must take care a little bit more. You can’t neglect this somehow.

If you see that tank size is more than enough for your fish species then the next you need to look is a proper nutritious food and here are the solutions for you.

Read here:- Best food for aquarium fish to make them grow faster

Ready-made food product for aquarium Fish


1. Optimum mini pellet

This ready-made food is nutritious for any type of aquarium fish except Oscars. Especially you can give this food to goldfish, platies, swordtails, molly, angelfish, cichlids and betta. But make sure that this is not for 1 year old fish. When your fish is little then you can give it. The specialty of this food item is it helps to reduce the stress of your fish. You can check the exciting discounted price of Amazon here today.

2. Glowfish special flake food


If you are keeping tropical or river fish in your aquarium then you should have this food product for fishes. This will help your fish to grow faster. Not only that, but this will help to regain energy also and after eating this food your aquarium will be active and colorful so much. But sometimes this product clouds the water which is not good. Go and check the exciting discounted price of Amazon here today.

Read here:- How long does it take aquarium fish to grow with comparison charts

3. Tetrabits complete fish food


If you have discus fish in your aquarium then just go and buy this food for it because nothing will be better than this for discus. As this granular nutritious food sinks slowly that’s why discus loves it very much. This is way better than frozen food. Not only discus, you can apply for tetra, harleyquin, zebra fish also. But you should not overfeed. Try to feed 3-4 times a day. You can check the exciting discounted price of Amazon here today.

4. Hikari Tropical massivore delite


This is a nutritious food and your fish will love it to eat. This is especially for carnivorous fish and that’s why smell is something bad. But if you can ignore it then the overall product is good for fish’s health. If you have Goldfish then you can feed it without any doubt. Red tail catfish, lungfish, string rays will love it if you give them to eat. But don’t overfeed your fishes. Go and check the exciting discounted price of Amazon here today.

Improper lights


Improper lights will not help your fish to grow faster. This will not work actively but in a passive way, this will prevent your whole aquarium growth.

If you want to keep fish healthy then you need to give it the proper environment which is similar to its habitat. Most fishes like to stay in the planted aquarium because fishes feel safe inside of plants and this type of aquarium keeps the environment better.

Now plants need proper lights to grow. When it gets proper lights then it will help to increase the DO (dissolve oxygen) level and that is very good for fishes.  Now when you will not provide lights then it will emit carbon dioxide and that is bad for fish’s health.

A study says that plants use yellow, green, orange, and violet intensity lights a little bit to grow. So you should remove your thoughts if you have planned to put this type of light in the aquarium. Instead of these, you can use soft white, actinic blue, and red for plant growth. This will help your plants to grow.

Water temperature


The temperature of the water is one of the most important things about fish growth. As fishes are cold-blooded species that’s why too many fluctuations of temperature can’t able to tolerate. So try to maintain a specific temperature and that should be between 13°C to 26°C.

Bad water condition


Bad water conditions may be a very big issue which will prevent the growth of your fishes. The main thing is that you can’t see or feel it and that’s why it’s dangerous. If you use tap water then you must know that your aquarium fishes are grown by consuming chloramine (chlorine +ammonia). You can’t even imagine how this chemical is destroying your fishes gradually and that may cause your fish is not growing anymore.

If you put well water then there may be a chance of containing heavy metals, or toxic chemicals with it. So that is also a dangerous thing.

To prevent things issue you must use or ammonia neutralizer which will help to give pure water which is good for your fishes. But water change is very much important. Don’t make a mistake by forgetting it even if you have a water conditioner.

Another healthy way is to prevent it is to make a planted aquarium. Aquatic plants can make your aquarium better even if you start with bad water unknowingly.      

You can check today’s discounted price of ammonia neutralizer on Amazon here.

Bad tank companions


Bad tank companions will create a huge negative effect on fish growth. Fish will not eat well if its tank companion is not good enough. It will be stressed all the time and it will hide and the ultimate result will be death.

So I hope you will not want that. Right? So try to choose the right companion for the right fish. Here I can help you to choose the right tank mate.

Final thoughts


If your fish is not growing that doesn’t mean that you have these problems. Maybe fish is juvenile enough. Most fishes grow faster at the time when it is sexually matured but after reproduction, its growth becomes slower again.

Still, there may be some hidden problems which I’ve discussed in this article. You should consider these problems if you see that your fish is not growing. I hope my solutions will work for you and your aquarium.

So best of luck & happy fishkeeping 🐟

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