What makes a tank overstocked?

[seefour5]

In theory when looking at a tank of any size, there’s a limit to the amount and size of fish you can put in it. However, I feel as though a lot of tanks can be “overstocked” and as long as parameters remain stable and the fish are happy, this is negligible. I’d like to get some more opinions on this, what would you all consider overstocked in a tank and is there room for this in all tanks? Do you feel your tank is overstocked? Thanks!

 

[Miami Reef]

When there is overcrowding.

 

[Nemo&Friends]

When there are not enough hiding places for each fish, which causes stress and increases aggression or even diseases.

 

[Lavey29]

I agree with the above however sometimes over stocking is manageable if you have a mix of top swimmers, mid tankers and bottom dwellers combined with sufficient filtration.

 

[Anemone_Fanatic]

Three things.

1) Nutrients are getting too high, too fast.
2) Fish are too crowded in, leading to stress and aggression.
3) When the tank is too full to look nice.

Obviously the third one is subjective, but I still factor it in. The temperaments of individual fish and the quality of the filtration systems vary, which is why "x inches of fish per x amount of gallons" isn't a good rule. There's too much variability.

 

[Jekyl]

Every fish in the tank should have its own individual hiding / sleeping safe place. If you dont have enough rocks/space to provide that, you're overstocked. Big reason I can't stand NSA tanks. They're not good for the fish, just egos.

 

[00W]

These are all good answers and you will get many if everyone chimes in.
It really is debatable as to size of fish, how fast they grow, size of tank and personal choice.
I believe in one fish per foot of tank so I have 3 fish in a 4 foot tank and one in a two foot tank.
But that's just me.
Some might think that is silly but I've always done it that way. Lots of rock and a few fish.
If you look through some of the members tanks you'll get a good/better idea of what you might want to accomplish.
@Jekyl said it well.

 

[o2manyfish]

I like lots of fish - Hence the screen name. While I have a real big tank now - 750g - I already have about 150 fish in the tank. I like little fish so there are lots of what I call doinker fish in the tank. But that's not to say it's all small fish - 3 yellow tangs (Adults), 3 Purple Tangs (adult), 6 hippo tangs, Sailfin tang (Adult), Flame tip tang (juvenile), Lavendar tang (juvenile), Achilles (Adult), Powder Blue (Adult) - Some medium sized angels. And from that size all the way down to a 3/4" clown goby. Nobody is getting their butt kicked. I find that even with aggressive fish within chaos you find peace. There are so many fish to chase that they just don't bother.

Some 'think', and I say 'think' because they have no actual experience with it, that 100 fish in a tank is way too many and unhealthy. In our prior 400g tank we had 140 fish - Including the same purple and yellow tangs. In that smaller tank we had a bunch of large angels as well. And at one point in that tank we had the following fish spawning (all at the same time) - Clowns, Bangai, Orange Tail Damsels, Frimandi, Golden Angels (Trio), Joculator Angels, Bellus Angles (Trio), Venustus Angels (Trio) and Goldflake Angels. That's a lot of fish to be happy enough to spawn in captivity. And some of those fish had never even been filmed spawning in captivity at that time.

Now in my many years of loving lots of fish, I didn' think I would ever hit a '2many' point. But in the 750g right now, from a visual standpoint, I think I have too many fish. There are still alot of fish I want to add to the tank to give it more life. But at the moment I think there are too many mid water column fish. There are almost 40 anthias, a dozen chromis almost 10 mollies that the wife wanted -- I don't mind the mollies - they are great algae eaters - but there are too many now for them to be cool.

The question is what am I going to do about it. I can easily see myself getting past 200 fish in this tank. But the mass of mid tank swimmers makes spotting all the lil subtle fish just too difficult. So I think I'm going to start whittling down the Anthias and the chromis.

Fish I still want to add to the tank are a trio of Golden Angels, a pair of yellow belly regal angels, more damsels, Borbonius, trio of gem tangs, more yellow tangs, 24+ Barnacle blennies, another dozen fire fish, so dragon faced pipefish, a pair of Joculator angels, a dozen assorted captive bred pseudochromis and the list goes on. We have 1 juvenile goldflake angel in the tank now, with a second growing up in the outdoor frag tank. Another few months are we will put the two of them together and hopefully have a new pair.

Dave B

 

[adinath]

I agree with the above however sometimes over stocking is manageable if you have a mix of top swimmers, mid tankers and bottom dwellers combined with sufficient filtration.

I agree with you here. Only thing I would add is introducing new ones will be challenging in this case. Overcrowding may create stress in my opinion

 

[i cant think]

Im intrigued on what others think of this, I personally overstock my tanks in other peoples eyes. In my eyes, I wouldn’t say it’s overstocked, I have the territory, food and swimming room for everyone. As soon as the territory is completely taken that’s when I think a tank is overstocked. You want enough territory for there to still be unclaimed areas for some fish. In my 4’ tank I have 19-20 fish. 10 of which are wrasses (so near enough half of them) and yes everyone is boisterous to similar species - my rabbits every so often have some issue with eachother but it’s not consistent enough to be true aggression.

 

[JoJosReef]

I think a lot of people consider overstocking in terms of bioload. But that's entirely dependent on the dynamics of your system. Do you have a tightly controlled system with limited microfauna or a sprawling food chain that processes every bit of organics you toss in? Are your corals growing so fast they consume everything your fish poop out or are you starting up with new frags? Most importantly for your fish, are they all being fed plenty and have enough personal space?

You might be overstocked with 10 fish at one point in your build but perfectly fine with 10 at a later time. No rule of thumb in my opinion, just monitor your tank and adjust as needed.

 

[radreef02]

Aggressive fish and too much bioload for your filtration

 

[Rob.In.AZ]

3 things that I think of with overcrowding.
Nutrient export - your tank/ filtration can't keep up with the nutrient input.
Stress/ aggression - so many fish that you start running into stress and aggression.

Both those seem to work themselves out, if you get me. Things die, then you've got less crowding. Not a great approach in my opinion.

The 3rd is mounting a metric ****ton of frags all right on top of each other. Should give them some room to grow out, and think about how they're going to look years down the road.

 

[Cell]

I can put 20 people in a bedroom and give them food and water and they will survive. But are they happy or thriving? Is it good for them long term?