# Symptoms of an overstocked tank



## Sterving (Dec 23, 2004)

Some fish may become aggressive toward others if swimming space is limited, but that depends on species. Also, an inch/gal rule of thumb may give you reasonable estimate.


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## Mori (Jul 23, 2003)

Plants generally help you get away with more fish. They do some water cleaning and provide more microhabitats for fishes that might otherwise come into conflict. But 5 gallons? I don't think plants can give you much leeway in such a small tank. You have to be a darn good aquarist to get away with "overstocking" something that small. 

Tell your buddy one inch per gallon, and that only goes for slim species that can coexist. A properly stocked tank has stable water parameters, the fishes have room to swim and have their own territories if they need them, and never SMELLS.


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## bigpow (May 24, 2004)

obvious signs of overstocked tank:
1) poor water quality: cloudy/stinky/foamy water
2) a change of pattern in fish behaviour
3) high mortality rate
4) filter gets dirty too quickly


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## uncskainch (Feb 22, 2005)

I think, too, that regular testing can help you determine if you're overstocked. If the % and frequency of water change you're comfortable with doesn't keep your nitrates in check, you're probably overstocked. Of course that's different for different people -- some may not mind doing 50% water changes 3x a week, while others don't want to do more than a 20% change every 2-3 weeks. 

And, as others have said, I'd consider any stocking situation that results in negative changes in fish health or changes in natural behavior to be a candidate for the overstocking label.


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## Hawkeye (Mar 22, 2005)

Along with high NO3 levels you will have a constant ammonia level too. 

Hawk


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## anonapersona (Oct 19, 2002)

Best indicator is probably nitrate, in that it is hard to argue with the nitrate test. 20 ppm is a good max level, 40ppm for a, um, shall I say lazy? fish keeper. Frequent water changes are the only good fix for this, though plants can help, they also can hurt if they are not healthy and die off. 

Most other things could be argued about; fish deaths, water quality, fish that jump or are aggressive. 

If the tank is over crowded and regular water changes have not been done and a large water change is required, be sure to do it slowly until the tank is closer to tap water conditions. I suggest 10% daily for 5 days, then 20% daily for 2 days or until the nitrate level gets to 20 ppm, then 50% a week thereafter. 

A huge water change can make the fish ill if the tank is very different from the tap water, smaller more frequent changes ease the fish into the different chemistry without huge changes in osmotic stresses that can damage gill cells.

So, a good fish keeper will change water when the tank gets to 20 ppm nitrate, and he will change enough water so that when he is ready to do it again, the tank is not yet above 20 ppm. So, if the tank starts out at 10 ppm, and the nitrates increase 2 ppm per day, a 50% water change will be needed at or before 5 days, or else you need to lower the starting level down with even bigger water changes or slow the increase in the nitrates.


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## BriNeShriMp (May 30, 2005)

The rule is one inch of fish per a gallon. Any more than that, and your overstocked.


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## lumpyfunk (Dec 22, 2004)

BriNeShriMp said:


> The rule is one inch of fish per a gallon. Any more than that, and your overstocked.


I belive that a more accurate measuement has to due with surface are in respect to fish length, but I cannot rember it. :icon_redf


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## algae (Mar 28, 2005)

Doesn't the width of the fish also play a role? ...you know, how a two inch skinny fish would be less of a load than a two inch fat fish.


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## fishmasterno1_2 (Jun 1, 2005)

I don't overstock so I have to add nitrates. Water changes are when I get to it Usually a few gallons a month. No problems here. Reduce fish add plants to make your life easier. my $.02


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## macbrush (Jun 2, 2004)

I always treat that 1cm per 2 litre rule (more or less 1 inch 1 gallon) as a guideline. As soon as I have to make estimation whether I am approaching that stock level, I would consider myself overstocking.

Can we just treat our fish like dogs, and cats? Give them some room.


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## anonapersona (Oct 19, 2002)

*Rule vs rule of thumb*



BriNeShriMp said:


> The rule is one inch of fish per a gallon. Any more than that, and your overstocked.


Now, that's just silly. There is no such Rule. That is simply a starting point, a rule of thumb. 

Then, you consider the mass of the fish (thin or fat), the feeding habits of the fish (messy or live foods), the need for companionship (schooler or solitary), the dimensions of the tank (tall holds less than wide), the water change schedule (bigger more frequent lets you add a few fish usually), the filtration (dual or triple filtration will let you add a few fish usually), general cleanliness of the tank, the need for swimming room, the compatibility of the different fish in the tank, the layout of the tank (enough areas for territorial fish) and finally, whether you have healthy live plants in the tank. 

So, for example, my 105 gallon tank has 100 true gallons in it by volume. I have 16 fish averaging 6" total length. 16 x 6 = 96, so you'd think it was perfect, eh? They are social but competitive fish, large and messy eaters. I compensate by doing frequent water changes, siphoning wastes daily, running 3 filters including a biowheel. I've added a few large fake plants to give more places to hide from aggressors. But, it is still overstocked and one day late on the water change and I see the result in increased fish aggression or fin problems.

So, please dont' quote that as Rule, it is certainly a "rule of thumb", but that is not the same as a rule.


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