Amount of fish a tank can hold?

[peter1209]

Hi,
I'm completely new to fish keeping and would like some advice as to what and how many fish my tank will take without over stocking.

I have just started the fishless cycle and everything is coming along nicely, I managed to get some used media from a friend so now provided I have done everything correctly it shouldnt be too long before the cycle is complete and I can start adding fish which brings me to my next problem.

The tank is about 90 litres or so, measurements are 82 (lenght) x 30 (width) x 40cm (height), I think its actually about 98 litres or something but lets just say its 90.

I have read the various "rule of thumb" posts with regards to so many inches per gallon, after using several calculators it came up with around 85 inches of fish, lets say that I stock male guppies only, after some research they grow to about 2" so according to the calculator I can stock 40 ish guppies. That cant be right for the size of my tank surely? I know common sense comes into this and 40 guppies in my tank would surely be way to crowded.

So if someone could offer a more sensible answer, I really very worried about overstocking the tank.

I understand to begin with to start small and add more fish as the tank matures which is totally fine, I want to try and build up a stocking plan for the next few months so I get it right from the start and not make any mistakes which will cause harm to the fish.

As this is my first time keeping fish I want to keep things simple, I have read/been told guppies are quite good starting out fish but I have also read they are no longer as hardy as they used to be and due to breeding for retail most found in fish shops are not suitable for sale, is this true? Looking at the various fish I love the look of cardinal tetra's, I also understand these are best suited to a mature tank so I can wait a few months for these no problem.

So lets say I want guppies, cardinal tetra's and a couple of those that feed on the bottom (little catfish type ones), will all these live peacefully together in the tank? If I start with guppies how many should I start off with? How many can I increase the population to? (i.e 6 guppies, 6 tetra's, 2 catfish things) Amounts and timescale for adding these would be very much apreciated.

I have been doing alot of reading and I really dont trust my local fish shops advice, they seem to give me very conflicting advice from what I have read on various forums,advised me against fishless cycle and said it was perfectly fine to do a fish-in cycle etc etc.

 

[Aquatic_Adam]

By the sounds of it, you have a good head on your shoulders! I am glad you are concerned for your fish

The "inch per gallon" rule is very antiquated. The size alone is not great thing to think about, you also must consider what strata (level) of the tank all the fish will swim in, activity levl, bioload, compatibility, aggresiveness, etc, etc.

I think Guppies are a great starting fish and are still very hardy comparitively. With a 90+ litres, I think you could easily start with about 5 Guppies. You don't want to add a lot at at time and shock your aquarium with the bioload. Corydoras (the catfish you were referring to) are also super hardy. I would wait a couple days and then add maybe 5 of those (they prefer to be in groups).

 

[peter1209]

I think I got a little mixed up with my calculations in my post, very confusing having gallons, us gallons and litres. Whatever the calculations for amount of fish was stupidly high or so it would seem.

5 Guppies seems like a good amount to start with, with regards to the Corydoras do you not have to wait a couple of months for the tank to mature before adding these, I was on the understanding they require enough algea (**** I cant spell) to be present which builds up over time.

This is certainly something I dont want to rush but lets say I wanted to add some more guppies after the intial 5 I started with, what is a reasonable period to wait and then if I wanted to add some cardinal tetra's, what is the maximum I can add of these?

 

[Aquatic_Adam]

I think I got a little mixed up with my calculations in my post, very confusing having gallons, us gallons and litres. Whatever the calculations for amount of fish was stupidly high or so it would seem.

5 Guppies seems like a good amount to start with, with regards to the Corydoras do you not have to wait a couple of months for the tank to mature before adding these, I was on the understanding they require enough algea (**** I cant spell) to be present which builds up over time.

This is certainly something I dont want to rush but lets say I wanted to add some more guppies after the intial 5 I started with, what is a reasonable period to wait and then if I wanted to add some cardinal tetra's, what is the maximum I can add of these?

Actually, that's a common misconception of Corydoras. They do not eat algae, but instead eat leftover flakes and great appreciate sinking pellets.

I believe your tank works out to be around a 25ish gallon tank. You could get a nice school of 10 or so Cardinals in there, but again, I would wait a bit on those as you want to make sure your tank is a little matured.

 

[peter1209]

Well by the sounds of it the guys in the local fish shop havnt a clue then, they advised that I can start with tetra's straight away and that I should wait for a mature tank before adding the Corydoras and that I could only get a max of 2 of them in my tank. I have read quite alot about tetra's needing a mature tank which is fine, i can wait for those, im a little suprised I can put as many as 10 in there, made me quite happy cause I think they are stunning little fish.

 

[librarygirl]

I think you'd be fine with the cardinals once the tank is finished cycling. You could do:
8-10 cardinals
6 corys (they prefer groups, minimum of 4)
3 guppies (they have a fairly high bioload and they can breed prolifically so I think 5 may be pushing it a bit)

Since you're fishless cycling you can add most of the fish fairly quickly once the cycle is done. I'd add either the group of corys or the group of cardinals first. Wait a week, test your parameters daily. If ammonia and nitrite stay at 0 (which they should if the tank was cycled properly), then you can add the other group. Wait another week, test, if all is OK add the guppies.

Also what substrate do you have? Corys have sensitive barbels that can be injured on sharp substrate. if you have sand or rounded gravel it should be fine. Be sure to keep the substrate clean as their barbels can also become infected from poor conditions.

What filter is on the tank?

 

[peter1209]

Ah well thats interesting with the corys, its like very small white stones not rounded so I might have to rethink about having those.
The filter I got was All Pond Solutions - 1000EF Aquarium External Filter - All Pond Solutions (All Pond Solutions 1000EF Aquarium External Filter).