overstocking question

[flyjawn]

without a doubt, by any traditional means of calculating how many fish to keep in an aquarium, my tank is overstocked.

i have a 20G high, planted with a 15W life-glo bulb. i have in the last 7 months accumulated the following fish:

8 Cardinals
7 Red Phantoms
6 Lemon Tetras
2 Bolivian Rams
2 Corys
2 Otos

that's 27 fish.

my tank water quality is perfect, i do weekly water changes of 25-50%. the fish are gorgeous and all the tetras like to school together. i have had no losses except one "cardinal vs intake filter" mishap.

my question is this: what are the reprecussions of overstocking a tank and what should i be looking for?

TIA.

 

[Zagz]

Ammonia spikes, stress, aggression and territorial issues come to mind as a few things to watch out for. Also overfeeding causing high nitrates. Certainly tanks that are overstocked can survive with proper care and maintenance and good filtration. It's not the quantity of fish that matters it is the space for the fish. Overcrowding can also cause stunted growth in some fish. These are the things IMO you need to watch out for.

 

[aquariumnoob]

it's probably the 50% water changes weekly thats keeping it stable. doing smaller changes twice weekly would help prevent the buildup if you notice things are rising. also if you have any friends that can take a few fish that would be good.

 

[plecoperson]

My tanks are also overstocked. When you look at them you see very few fish (unless it's feeding time). In my case, I do a 50% water change weekly too, and overfilter the tanks.

I also favor very tiny fish, which makes a difference. Only the bristlenose plecos, female bettas and sparkling gouramis are territorial, and all of those are in a 75 gallon with plants and driftwood aplenty, so they can stay out of each other's faces.

Overstocking does make tanks kind of a ticking time bomb-much less margin for error if something goes wrong. Honestly, I'm home much of the time when not working, and watch them constantly.

I would say that the fish do well and seem "happy", and the tanks don't look overcrowded. I would certainly not recommend that anyone push the limits like this. In retrospect I wish I'd put more thought into what I really wanted, just to make the tanks easier to care for!

 

[corster]

I have a heavily overstocked 29. I do a 5 gallon water change every 1-2 days to keep my nitrates down. I keep them no higher than 20 ppm. I also am filtering 300 GPH.