Stocking Recommendation

[mark4785]

I currently have a 120 litre high-tech aquarium stocked with 4 black neon tetras and 4 albino corydoras. As corydoras, for me, look more spectacular when they are in a large shoal I have been thinking about adding more albino corydoras to the aquarium. The issue I have is determining how many more corydoras I could safely add and how many at a time I should add. 
 
I personally think that adding 2 new corydoras every 1 month for a period of 2 months would not result in ammonia and nitrite inflation. I think this because the aquarium has an abundance of plants from front to back and the aquarium filter was seeded with nitrosomonas/nitrobacter colonies on a sponge taken from my pond filter (around 1 year ago) which has been running for 7 years and takes a huge bio-load.
 
Any opinions on the stocking would be greatly appreciated.

 

[nortonmad213]

both the tetras and the cories should be in shoals of 6 or more.
i think with the seeded filter already it should take any stocking you throw at it

 

[Wills]

If Im reading it correct, the tank is a year old and the filter sponges are from a 7 year old pond? If so I wouldnt hesitate to add more fish as Nortonmad says the shoaling fish will appreciate higher numbers. It depends on what you want to do with the rest of the tank but 8 of the Tetras and Cories would be a good start and then look at adding some centre piece fish like some dwarf cichlids, Lateacara Dorsiger are a particular favorite of mine but things like Bolivian Rams, any of the Apistos would work.
 
If Im correct in the above I would add 4 of the Tetras then 2 -3 weeks later add the 4 more Cories. Just make sure the cories are all the same kind But with them being Albino they are probably Albino Bronze Cories so you could do some regular Bronze Cories to go with them as they are the same fish giving off the same hormones and signals as each other they just look different which wont be as much of an issue for the fish.
 
Wills

 

[Rexenator]

If you follow the rule of thumb 1 gallon for each inch of grown fish, 120L is around 30 gallons. Tetra are 4x 1.5" and corries are 4x 2" that's 14" total. You could easily double the numbers, especially with the bio filtration you have.

 

[attibones]

If you follow the rule of thumb 1 gallon for each inch of grown fish, 120L is around 30 gallons. Tetra are 4x 1.5" and corries are 4x 2" that's 14" total. You could easily double the numbers, especially with the bio filtration you have.

This "rule" is not something to always adhere to, keep in mind. It doesn't take into consideration the three main levels in the water, as well as potential size of a single fish, or bio-load.

In this instance, because both fish occupy different areas of the tank, eight of each, plus perhaps a show fish (perhaps on the top layer) would not overstock the tank. Your calculations prove that the "rule" does work for small species, but it is not a law.

 

[Rexenator]

If you follow the rule of thumb 1 gallon for each inch of grown fish, 120L is around 30 gallons. Tetra are 4x 1.5" and corries are 4x 2" that's 14" total. You could easily double the numbers, especially with the bio filtration you have.

This "rule" is not something to always adhere to, keep in mind. It doesn't take into consideration the three main levels in the water, as well as potential size of a single fish, or bio-load.
In this instance, because both fish occupy different areas of the tank, eight of each, plus perhaps a show fish (perhaps on the top layer) would not overstock the tank. Your calculations prove that the "rule" does work for small species, but it is not a law.

Yeah I guess I should have mentioned that. For instance, I would never directly apply this rule to my goldfish tank because of the bio load. But it still is a reasonable quick check when applied with that in mind.

 

[hobby5]

I would advice against adding any cichlids with the corys as they occupy the same level.

 

[attibones]

I've kept rams with corydoras. Provided you have plenty of hiding spaces and plants and an appropriate school of corydoras, they don't bother each other usually. Of course, there also is the possibility of a really grumpy ram, but most apistos or microgeos like the GBR do well.

 

[Wills]

I would advice against adding any cichlids with the corys as they occupy the same level.

 
I think there are tons of Cichlids that can be kept successfully with Cories - In the past I have kept Cories with Angels and Keyholes and at the moment I keep a Severum, Threadfin Acara, Burjaquina and a group of Cupid Cichlids with Dwarf Hoplos and Flagtail Catfish for the past 5ish years (maybe more) There are dozens of dwarf cichlids that would replicate similar relationships in this size tank, Nannacaras, Laetacaras, Bolivian Rams, some Apistos, Checkerboards. Bronze and Albino are one of the larger species so could even work with larger mid sized like Yellow Acaras and Krobia - though these two would not work with the tetras. I mean not all at once but there are ways to do it in this sized tank .
 
Wills