Overstocking

[MaxM]

This is probably a difficult question to answer.

I've been into the hobby for about half a year now and I've watch A LOT of videos on the hobby to familiarize myself with the basics. 

One issue I still find hard is figuring out what is the breaking point between a nice stocked tank and an overstocked tank. As we all know, there is constant craving for MORE. We all have to deal with the thoughts of, "What else can I add to my aquarium?", "What's missing?" 

Obviously, better to understock than to overstock. However, there are situations that warrant considerations. For instance, I have three swordtails ( 1 male and 2 females). Now I know you're all thinking the same thing... 1 to 3 or 4 ratio! I realize that too, but have been hesitant to add another because of my concern of overstocking. I could give specifics on my tank size and what I have stocked, but that deflects the purpose of this topic. I want this topic to be helpful guidelines for anybody new to the hobby. 

I'm interested in hearing what YOU use as a rule of thumb of how much to add to your aquarium.

[Daniel]

I don't want to be slum lord trying to calculate just how many more tenants I can squeeze into a tiny apartment before the breaking point of filth and disease take their toll.

Here is what I do. I stock the tank as if there were no filter and no airstone (almost as if the aquarium was a big betta bowl). You are guaranteed not to overstock that way.

Why use this method?

You have happier healthier fish in cleaner water. As you can read on this forum, sick fish are no fun.

 

[MaxM]

47 minutes ago, Daniel said:

I don't want to be slum lord trying to calculate just how many more tenants I can squeeze into a tiny apartment before the breaking point of filth and disease take their toll.

Here is what I do. I stock the tank as if there were no filter and no airstone (almost as if the aquarium was a big betta bowl). You are guaranteed not to overstock that way.

Why use this method?

You have happier healthier fish in cleaner water. As you can read on this forum, sick fish are no fun.

 

If I would do that I would have one lone Angelfish trying to figure out where everybody went. 🙂

I understand what you mean though. Interesting food for thought. Thanks.

[Sleepy]

1) What size tank do I have or want to get.

2) What type of fish do I like and want to keep.

3) What are the care requirements for the fish ie. How big of a tank will they need when full grown, how many should be kept together, temps, food, what could be good tank mates, can I use live plants.

4) What type of filtration

5) Start with just a couple of fish unless a group is recommended and see how it goes see how your water is doing (testing) and slowly add fish over time.

[yannachka]

overstocking is a touchy subject since it is so hard to define. i define it by the water quality, if you have to fight to keep the water quality up then it is overstocked. i have one tank that many would consider overstocked but at this point, maintenance is pretty easy with 2x 50% water changes a week, the moment i start seeing that that is not enough i know the fish have outgrown the tank and need to be moved.

overstocking is all about how much work you are willing to put in. if you want a low maintenance, water change once a month, kind of tank then anything that would require you to do a water change more than once a month would be considered overstocked. if you have an auto water change system and you can continually provide clean water then overstocking is practically impossible, you can keep a 12” goldfish alive in a 5g tank that way. the morals and ethics of keeping fish in improper and too small tanks is a whole other discussion. 

figure out how much work you want to do to keep the fish healthy and dont fall into the trap of “i will definitely keep up water changes every 2 days” because we all know life happens and that plan will likely fall apart in 6 months. 

[MaxM]

2 minutes ago, Sleepy said:

5) Start with just a couple of fish unless a group is recommended and see how it goes see how your water is doing (testing) and slowly add fish over time.

Your last point is significant. That is a good way of making sure not to overstock by adding slowly and seeing how it affects the water parameters. Thanks. 🙂 

[MaxM]

4 minutes ago, yannachka said:

overstocking is a touchy subject since it is so hard to define. i define it by the water quality, if you have to fight to keep the water quality up then it is overstocked. i have one tank that many would consider overstocked but at this point, maintenance is pretty easy with 2x 50% water changes a week, the moment i start seeing that that is not enough i know the fish have outgrown the tank and need to be moved.

overstocking is all about how much work you are willing to put in. if you want a low maintenance, water change once a month, kind of tank then anything that would require you to do a water change more than once a month would be considered overstocked. if you have an auto water change system and you can continually provide clean water then overstocking is practically impossible, you can keep a 12” goldfish alive in a 5g tank that way. the morals and ethics of keeping fish in improper and too small tanks is a whole other discussion. 

figure out how much work you want to do to keep the fish healthy and dont fall into the trap of “i will definitely keep up water changes every 2 days” because we all know life happens and that plan will likely fall apart in 6 months. 

Your comment reminded me of a point we often don't take into consideration. Yes, water quality is of extreme importance. However, has anyone researched whether fish get stressed from overcrowding? I always find it amazing when I go to fish stores and sometimes see tanks so filled with a certain stock that I wonder if the fish are being stressed out because of it. Imagine, hypothetically, placing 100 goldfish in a 30 gal tank that has constant auto water changes where the water parameters remain perfect. As far as water quality is concerned it wouldn't be considered overstocking. However, space wise that would seem way overstocked! I can always increase my water maintenance (assuming I'm not lazy). However, how do I determine if my fish feel crowded?

[MickS77]

5 minutes ago, MaxM said:

has anyone researched whether fish get stressed from overcrowding?

I don't know if its "researched" but purposeful overcrowding is done in some African Cichlid tanks as a way to reduce stress and aggression. The idea being its harder for one fish to be singled out and harassed in large group. 

[yannachka]

1 hour ago, MaxM said:

Your comment reminded me of a point we often don't take into consideration. Yes, water quality is of extreme importance. However, has anyone researched whether fish get stressed from overcrowding? I always find it amazing when I go to fish stores and sometimes see tanks so filled with a certain stock that I wonder if the fish are being stressed out because of it. Imagine, hypothetically, placing 100 goldfish in a 30 gal tank that has constant auto water changes where the water parameters remain perfect. As far as water quality is concerned it wouldn't be considered overstocking. However, space wise that would seem way overstocked! I can always increase my water maintenance (assuming I'm not lazy). However, how do I determine if my fish feel crowded?

i dont think much research has been done but i may be wrong. that is why i mentioned the ethics of overcrowding and why i personally try to ensure that my fish have at least the basic needs met in terms of space. back when i bred bettas i still kept the males and females in proper tanks even though it is very common for breeders to house their breeders in jars or 16oz deli cups. im speaking in regards to the actual breeders, not the fry that do need to be jarred while they’re being raised, no way to realistically avoid that unfortunately. it is definitely species dependent though, i doubt crowding tetras in a tank would cause as many issues in terms of the fish’s well-being/stress as crowding something like plecos or a more aggressive cichlids. im really not a fan of the large, overcrowded monster tanks we tend to see. bigger is not always better imo but that’s a discussion for a different thread. 

[Irene]

Funnily enough, we just released a blog article called How Many Fish Can I Put in a Fish Tank? with some general guidelines on stocking levels. Enjoy! 🙂

(Image taken from the blog post)

[MaxM]

Kudos to "A Gamer's Wife". You going to put out a video as well, perhaps?

[Paul]

@MaxMI think if you can't keep your parameters stable (ammonia spikes for example) no matter what you do you've probably overstocked the tank. If you keep African lake cichlids overstocked tanks are a way of life. If they're not living in close quarters the aggression levels go off the charts. 

Edited October 15, 2020 by Paul

[FrostiesFishes]

How often do you wanna change water? That’s the real question. It’s kind of a science experiment. I have a 72 bow front that the internet would catch fire if they saw how many fish were in it. And yet I have no issues. 

[MaxM]

6 hours ago, FrostiesFishes said:

How often do you wanna change water? That’s the real question. It’s kind of a science experiment. I have a 72 bow front that the internet would catch fire if they saw how many fish were in it. And yet I have no issues. 

Can we see? 🤣

[Kyogadude]

When I find myself wondering this question on adding more fish I have figured it out by adding two things to the tank. ONE fish and ONE plant. Add more plants and you will have more peace of mind adding that additional fish.

[yannachka]

17 hours ago, FrostiesFishes said:

How often do you wanna change water? That’s the real question. It’s kind of a science experiment. I have a 72 bow front that the internet would catch fire if they saw how many fish were in it. And yet I have no issues. 

i have the same experience with my goldfish tank, i dont show it on the internet 😂 although i did make a post here forever ago

[MaxM]

22 hours ago, Kyogadude said:

When I find myself wondering this question on adding more fish I have figured it out by adding two things to the tank. ONE fish and ONE plant. Add more plants and you will have more peace of mind adding that additional fish.

Wow! That's the first time I've ever heard someone say that! That's a real interesting approach. Never thought of that, but I can hear the logic behind it. Did you learn that from someone or came up with that on your own? 

[Kyogadude]

I think i came up with it. Lol. But i just follow @Cory way of thinking of letting plants clean my water. My thought process is more plants allows for more fish so I add one to one

[Marc]

Each case is specific to the tank size, filtration, maintenance, plants, and inhabitants. I am a bit lazy and don't want to do many water changes once the tank is well established. I do regular testing and have lots of plants. I also have mostly small fish but quite a few. My large tank can still look a bit bare at times. For my small tanks I don't ever put many fish in them unless I am quarantining.  Small tanks can fluctuate much easier than large tanks. Any additions to them need to be monitored closely.

This is not my rule but I'm guessing I average about 1 inch per gallon in my large tank and 1 inch per 2 gallons in my small tanks. All my tanks have plants.

If you feel you are near capacity, as fish get bigger you may need to move them out as their waste load increases with their size.

[MaxM]

1 hour ago, Marc said:

Each case is specific to the tank size, filtration, maintenance, plants, and inhabitants. I am a bit lazy and don't want to do many water changes once the tank is well established. I do regular testing and have lots of plants. I also have mostly small fish but quite a few. My large tank can still look a bit bare at times. For my small tanks I don't ever put many fish in them unless I am quarantining.  Small tanks can fluctuate much easier than large tanks. Any additions to them need to be monitored closely.

This is not my rule but I'm guessing I average about 1 inch per gallon in my large tank and 1 inch per 2 gallons in my small tanks. All my tanks have plants.

If you feel you are near capacity, as fish get bigger you may need to move them out as their waste load increases with their size.

1) Where do you draw the line between what is a big tank and what is small?

2) Where I live aquariums are very expensive. A 55 gallon tank will run me around $300. That is why I need to be careful not to overstock. I don't have easy options and was fortunate enough to get a 25 gallon tank for free.

[JRed]

4 hours ago, MaxM said:

1) Where do you draw the line between what is a big tank and what is small?

2) Where I live aquariums are very expensive. A 55 gallon tank will run me around $300. That is why I need to be careful not to overstock. I don't have easy options and was fortunate enough to get a 25 gallon tank for free.

I think a large tank is relative to what kind of fish you are keeping, a 55 is large for a moderate colony of guppies but somewhat small for large haplochromis from Lake Malawi. I like to look at aquariums based on dimensions and inhabitants rather than gallons, giving them plenty of room to swim around (or swim away from one another) and how those fish fit into a tank. I think nowadays anything under a 30 gallon is considered "smaller", 30-75 gallons is considered medium, and anything above a 75 is considered "larger" but again would depend on what you are keeping. 

Thats a bummer to hear that glass constructed tanks are so expensive where you are from, have you considered setting up some plastic tote containers? I use these all the time for quarantining and raising fry. They are light, easy to disinfect and can stacked together so storing them is a lot easier. Just a thought.

[Daniel]

5 hours ago, MaxM said:

1) Where do you draw the line between what is a big tank and what is small?

If you have to tear down a wall and use a forklift to bring the aquarium into your house, you might have big tank. 🙂

[KBOzzie59]

28 minutes ago, Daniel said:

If you have to tear down a wall and use a forklift to bring the aquarium into your house, you might have big tank. 🙂

You need to add some water, some of that wood is not wet!  Probably should get some scuba gear first.

[Daniel]

5 minutes ago, KBOzzie59 said:

You need to add some water, some of that wood is not wet!  Probably should get some scuba gear first.

My wife and my children have both been in the aquarium doing maintenance. I’m not sure I have been forgiven yet for the time I had her change out the substrate.

[MaxM]

6 hours ago, JRed said:

I think a large tank is relative to what kind of fish you are keeping, a 55 is large for a moderate colony of guppies but somewhat small for large haplochromis from Lake Malawi. I like to look at aquariums based on dimensions and inhabitants rather than gallons, giving them plenty of room to swim around (or swim away from one another) and how those fish fit into a tank. I think nowadays anything under a 30 gallon is considered "smaller", 30-75 gallons is considered medium, and anything above a 75 is considered "larger" but again would depend on what you are keeping. 

Thats a bummer to hear that glass constructed tanks are so expensive where you are from, have you considered setting up some plastic tote containers? I use these all the time for quarantining and raising fry. They are light, easy to disinfect and can stacked together so storing them is a lot easier. Just a thought.

I started off with buying a small plastic container (about 2 gallons) when my 8 year old son came home with 6 mosquitofish that his friend "generously" gave him for free. 😞

From there, I moved on to buying a bigger 10 gallon container and adding some fish that had color. As time went on my son convinced me to upgrade to a 15 gallon plastic tote and the fish remained there until about a month ago when I finally was able to get a 25 gallon tank that someone was going to throw out. So I still have the other plastic containers, but I am using them for Fry.

BTW - be careful when buying a plastic totes. I did not consider when I bought my largest tote that the larger amount of water would cause it to bulge. I was always worried that the plastic would eventually give and I'd lose all the fish. If you get a large container make sure the thickness of the plastic is thick enough to sustain the heavy weight of water.