7 replies to this topic

[Betta132]

There are three factors to check:

Appearance (least important)

Fish stress level/aggression

Water parameters

Test the water right before you do a water change. If nitrates are over 40 (over 20 for ultra-sensitive fish) you need to do water changes more often or reduce stock level. For example, a frogfish probably has enough space in about 30 gallons, they're very sluggish. However, the tank is overstocked due to the fact that frogfish are MESSY MESSY MESSY. If you do daily water changes, it's fine so long as parameters are stable.

If the fish are anxious/stressed/aggressive, they need more space. For example, a fully grown yellow tang (7") won't dirty up a 75g tank terribly fast, but it'll become stressed and aggressive because it doesn't have enough swimming space. Also, a gulper or hyper-aggressive fish renders a tank fully stocked, because you can't put anything else in. In addition to that, a tank with a bunch of some variety of fin-nipper is fully stocked, due to the fact that most if not all new arrivals will be pestered and attacked far too much for it to be good for them.

Appearance is least important, but a tank is overstocked if it looks overstocked to you and you don't like the look.

If the stock level looks good, parameters are fine, and fish are all completely un-stressed, you aren't overstocked.

Just post a potential stock list here and ask. There are experts who can tell you if your tank is overstocked until you learn a bit more.

 

Now, I will stay this: the inch-per-gallon rule is actually an okay way to estimate stock level, provided we're dealing with a tank over 30g (smaller if only tiny fish) and smallish fish. For example, 10 1-inch neon tetras in a 10g is fine. Works well for fish up to about 4", I'd say. It's only an estimate, and it doesn't take into account the swimming-space needs, but it works reasonably well.

Edited by Betta132, 31 January 2015 - 10:03 PM.

[Matt DeLaVega]

Stocking density is personal preference, and management. In my 240 at one point I believe I had 20-30 pounds of fish. With fluidized bed filters, and regular water changes, they were in great shape, and seemed plenty happy. Do what you like, feel comfortable with and are willing to manage. No hard rules.

One inch per gallon is fine if you are concerned about the fish feeling crowded, and don't want to change water often. If you want a lot of action go for more!

[strat guy]

There's no such thing as over-stocked, only over-stressed and under-filtered!

 

One sunfish in a 75 will probably be very happy. No filtration and he will be very unhappy. Thirty sunfish in a 75 with 3 fluidized bed filters, a sump with trickle filtration and weekly 50% water changes will have very clean water. However, they will be very stressed.

 

Thirty shiners in a 75 will be very happy. A tiny canister filter and they will not be happy for long. One shiner in a 75 with three fluid bed filters, etc. will have very clean water, but once again will be extremely stressed out.

 

It all depends on what you are doing. Just remember the African Cichlid rule- over stock and over filter. The guys who keep those things keep too many of them, and they do it on purpose. The trick is to match the filtration to the fish load. As long as the fish are happy with the numbers that you're keeping them in, you just need to make sure there's enough filtration to match them.

[Michael Wolfe]

Wait a minute there... that is not necessarily the right answer for every fish.  I agree with you there is not one answer to this question... including the one you gave.

 

There is absolutely no reason to over stock and over filter a shiner tank for example.  40 shiners in a 75 gallon tank look great and require minimum work to maintain a canister filter and a bunch of live plants.  Similarly, a 25 gallon heavily planted tank with 5 Enneacanthus requires no filter at all, and minimal maintenance.  Now, these are my choices because they are easy and stable tanks... they are not maximally filled, but they are pretty, natural and easy to maintain.

[strat guy]

I think you misunderstood me  I wasn't saying to overstock every aquarium. What I was saying is that it simply depends on what you're doing. The African Cichlid thing works well... for African Cichlids. If you followed the 1" rule with them, they would kill each other. All I was saying is that what is really important is keeping the fish according to species standards, and making sure your filtration is up to the task. If filtration is simply some plants in a dirted aquarium, and its done without stressing the fish either in its company or in the tank's water chemistry, then you're doing it right. If however, you're overstocking and over filtering, and the fish are happy and not stressed, that can be right too. It just all depends on the set up. That's why I gave the examples of sunfish vs shiners. Shiners want lots of tank mates, sunfish want elbow room. Species standards change from fish to fish, and if crowding a fish makes it happy, then you should do that. On the other hand, if a fish wants to be alone, you should do that too, or else in most cases he will see to it that he ends up alone anyway.

Edited by strat guy, 03 February 2015 - 11:48 PM.