Overstocking In Fish Shops?

[NewBea]

Why is it that overstocking is such an important issue but every fish shop seem to have dozens of fish in totally unstimulating small tanks - no plants, hiding place or substrate etc?
Is it because crowding same type of fish together is not as much of a problem? Or is it because they are only meant to be that way for a short while until they are being sold? But what is a short while? Even a few weeks can cause be harmful, isn't it?
I know they are there to be sold, but if overstocking causes health issues then practically all fish bought from fish stores are already weakened due to the crowded situations.
No wonder that are so many people with overstocked tanks at home if that's what they see in the shops as well.
Anyone can shed some lights?

 

[fluttermoth]

Most fish shops have huge filtration systems (many on a sump) that significantly increase the actual volume of water that the fish are in, even if that water isn't contained in the tank.

The fact that most fish are only there for a short time is also a factor.

 

[NewBea]

Most fish shops have huge filtration systems (many on a sump) that significantly increase the actual volume of water that the fish are in, even if that water isn't contained in the tank.

The fact that most fish are only there for a short time is also a factor.

So that explains the sufficient water quality, but what about the area they need for swimming?
And does this means in theory, that if you have a big enough filter in your tank (bigger than what would be required) then it would be able to cope with more fish per gallon than normal?

 

[Chad]

Fish shops don't plan on keeping the fish in that condition long term. They expect to get the fish in and out before the problems associated with overcrowding arrise. They "get away with it" because it is a temporary condition that should last only a couple of weeks. We plan on having our fish around for years. Great question.

 

[fluttermoth]

So that explains the sufficient water quality, but what about the area they need for swimming?

Well, as Chad says, they're relying on the fish not being in stock long enough for stunting/lack of swimming space to become an issue.

And does this means in theory, that if you have a big enough filter in your tank (bigger than what would be required) then it would be able to cope with more fish per gallon than normal?

No, not really. Stocking is limited by the amount of nitrate produced. The kind of filtration I'm talking about (sumps, that most fish shops use) are an actual, whole extra tank that contains filter media; this can double the actual volume of water in the system.

 

[NewBea]

So that explains the sufficient water quality, but what about the area they need for swimming?

Well, as Chad says, they're relying on the fish not being in stock long enough for stunting/lack of swimming space to become an issue.

And does this means in theory, that if you have a big enough filter in your tank (bigger than what would be required) then it would be able to cope with more fish per gallon than normal?

No, not really. Stocking is limited by the amount of nitrate produced. The kind of filtration I'm talking about (sumps, that most fish shops use) are an actual, whole extra tank that contains filter media; this can double the actual volume of water in the system.

Such a shame! I was hoping to fit about 50 fish in my 25 gallon tank I thought I can get away with a small tank/cheap maintenance and all the fish I want.
(Just kidding of course)

 

[Chad]

You can get away with more small fish if you up filtration. I love to keep nano fish like ember tetra and chili rasbora. Because they require little swimming room you can have more of them if you have proper filtration so there is some truth to the notion depending on the species you are wanting to keep. This is also one reason sumps are becoming more and more popular and not just for reef tanks anymore.

 

[Mikey1]

there are only two factors when it comes to stocking,

- the fishkeepers knowledge
and
- how well the fishkeeper maintains the tank

thats it,

all this one inch per gallon theory is rubbish....that is simply a general guideline for the "average" fish keeper with "average" knowledge.....i could very easily pack 50 inches of fish in a 20 gallon tank and all the fish would be very happy and healthy, but then again im an expert with over 25 years experience, so not something i would recommend for a novice or intermediate,

most fish stores use undergravel filters, which provide a very large area for bacteria, and the bacteria is accustomed to dealing with a large waste load, undergravel filters are the best filters out there if properly maintained (that is the key), fish stores also do very frequent water changes, and they do not feed their fish much which also cuts down on the fish waste,

 

[Chad]

Well...the fishkeeper's knowledge covers a lot. For me I use quite a few criteria to pick fish that fall under that category. I've posted the list before.

1.max fish size
2.temperament
3.type of food
4.quantity of food
5.metabolism
6.fish compatibility
7.coral compatibility
8.invert compatibility
9.substrate requirements
10.swimming requirements
11.swimming ability
12.flow requirements
13.sensitivity to changes in parameters
14.sensitivity to water quality issues
15.sleeping habits
16.rock work requirements
17.lighting preference
18.body shape (deep keeled vs shallow)
19.territorial requirements (I can only keep 1 male clown goby in my 210 gallon tank and that fish is tiny).
20.escape and jumping potential
21.temperature requirements (temperate vs tropical also temp range and how temp affects metabolism)
22.growth rate

My knowledge of the above and my husbandry practices are what help me decide on what to put into a tank.

 

[CausticKat]

Also, I work in an small store that is part of a national company. No matter how much I advocate a stop to overstocking there are guidelines in place that must be followed or there are repercussions that effect all the employees not just the aquatics department.

We do however have a very well developed sump system to try and compensate for the large numbers of fish in our tanks. And if there is ever a problem with a sump or tank there are procedures in place to minimize the stress.

 

[Baccus]

As already stated most fish shops/ pet shops have substanstial filteration often a large sump tank which may be filtering any where from 4 to 6 tanks. My local pet shop has this system where they have basically 6 tanks to one huge sump filter packed with as much media to support filter bacteria as possible. These banks of tanks are set up for each type of fish. For example all the guppies, mollies, platties, swordtial, sailfins and any other fish that will like/ tolerate hard water are set up with their own bank of tanks and sump. Then the soft water fish like tetras, gouramis have their own banks of tanks again with a seperate sump. This continues on to the cichlids through to the marine fish. As well as heavy filteration these tanks are also having frequent water changes and topping up, so there is almost a constant supply of new or clean water coming into the tanks. This in turn reduces the potential of harm being caused to the fish from a build up of growth suppresent hormones being produced by the fish in these tanks.

Also as previously stated most fish shops buy in bulk, not only because they expect some losses, but also because they don't expect the fish to remain in their tanks for weeks or months. Even my local pet shop will only special order in fish for me, because they know I will take all that I ordered and they will not be stuck with a "specialist" fish for months on end.

Only one of my local petshops has bare tanks with only gravel on the base, most of my local ones do have some timber/ rocks even plants in the tank. But the sad fact is the more things they put in the display/ sale tanks the more things they have to remove in order to catch the fish people wish to buy. So its a bit of a trade off, to have a wonderfully scaped tank, being dismantled possibly 4 or 5 times a day or only have a couple of things in the tank for ease of capture of the fish in there.

I like one of my local pet shops especially because not only have they set up a beautiful marine show tank ( have offered to buy it

but the owner wont part with his pride and joy

) they have also set up a fresh water display tank complete with plants, huge peices of timber and suitable community fish. These display tanks are able to show people what is possible, without being destroyed everytime a fish is purchased.

 

[NewBea]

there are only two factors when it comes to stocking,

- the fishkeepers knowledge
and
- how well the fishkeeper maintains the tank

thats it,

all this one inch per gallon theory is rubbish....that is simply a general guideline for the "average" fish keeper with "average" knowledge.....i could very easily pack 50 inches of fish in a 20 gallon tank and all the fish would be very happy and healthy, but then again im an expert with over 25 years experience, so not something i would recommend for a novice or intermediate,

most fish stores use undergravel filters, which provide a very large area for bacteria, and the bacteria is accustomed to dealing with a large waste load, undergravel filters are the best filters out there if properly maintained (that is the key), fish stores also do very frequent water changes, and they do not feed their fish much which also cuts down on the fish waste,

That makes a lot more sense than the "inch per gallon" rule!

Tcamos - that's a very useful list to keep in mind! As I'm only new to fish keeping I ended up selecting livebearers only. I looked into dozens and dozens of different fish online only to find that they either require different water ph, temperature or substrate to what I have; or fish that wouldn't mix so well with what I already had. I think livebearers are reasonably easy to keep and they come in a huge variety of colour and pattern to make the tank look nice.

Baccus - I found your post very interesting - now I understand that the fish are not only organised being next to each other based on look/family but because batches of them are running on the same filter with same sort of water requirements - and indeed they are organised exactly the way you said in our fish store as well.

 

[daizeUK]

For example all the guppies, mollies, platties, swordtial, sailfins and any other fish that will like/ tolerate hard water are set up with their own bank of tanks and sump. Then the soft water fish like tetras, gouramis have their own banks of tanks again with a seperate sump.

When I was looking for platties & guppies in our large aquatic store, I had to look all over the shop for them. There were tanks of platties and guppies interspersed amongst all the soft water fish, here and there with no apparent organisation. Is that a sign they might be running off the same sump?

Think I will ask them next time I visit.

 

[Baccus]

For example all the guppies, mollies, platties, swordtial, sailfins and any other fish that will like/ tolerate hard water are set up with their own bank of tanks and sump. Then the soft water fish like tetras, gouramis have their own banks of tanks again with a seperate sump.

When I was looking for platties & guppies in our large aquatic store, I had to look all over the shop for them. There were tanks of platties and guppies interspersed amongst all the soft water fish, here and there with no apparent organisation. Is that a sign they might be running off the same sump?

Think I will ask them next time I visit.

It maybe that they had seperate sumps for the various fish species, or that they just used all the same water for all the fish and didn't see a problem with having hard and soft water fish mixed up together.
My local shop that buys my guppies knows that I have mine in soft water so when they get my guppies they deliberately put them over in the soft water section, well away from the mass produced/ farmed fish which have salts added to their sale tanks. What I get a real kick out of seeing is my locally bred guppies get sold before the mass farmed ones

, its amazing what good genetics, care and food can produce.
I would ask your local shop about their filteration setup, it might be something they have never considered.

 

[MBOU]

All our Systems are run off of sumps, each sump is 5x2x2 in size and split in half, the whole lot is filled with kaldnes biomedia and one side is aerated and the other is not and the water is passed through the sump. The sump not only collects the dirt and passing water through a massive colony of bacteria but also the aerobic and anaerobic baceterias too that break down even nitrates.

Bigger systems maybe have more filters but our systems are either 4.5k liters of 2.8k liters or thereabouts. Some shops dont have soft water systems and so it doesnt matter which systems the fish go on but common sense would say that livebearers go on one system and tetras another etc..

Because of the high turnover on the systems (the bigger has an 18,000 lph pump on it and the smaller a 12,000 or 15,000 lph pump!!) and the really small pipework needed (and lots of it that needs cleaning all the time!) having more than one rock or plant in a tank can stop the flow to the weir and mean the tanks get a lot dirtier.

Also too much decor makes it very difficult to gravel clean!! I have the wonderful job of gravel cleaning 120 tanks at least once a week but generally twice if i can fit it in round customers and I can seriously tell you, messing about with the coverslides is a pain, having to stop to pull out decor before doing each tank can make it so much harder!! The fish would rather have more room to swim and less decor and a cleaner tank for a few weeks than be hemmed in. You will notice in most shops that there are exceptions to the rules... our coldwater gobies and hillstream loach have loads of pebbles and our dwarf cichlids have several rocks and bits of wood to break up territories.... but for things like livebearers and tetras, decor collects a lot of food (and bear in mind... shop fish are often fed 3-5 times a day!) and the fish are more delicate to nasties in the water like rotting food and dirty grim tanks.