okay thanks for all replies people xox

I personally would not recommend Geophagus spp. in such a small tank. Some species may not grow very big, but they are very sensitive to water quality issues (they get hole in the head for example) if the water is not top quality. By keeping them in a larger tank, it improves the amount of time before the water gets too bad.

Many Geophagus species are also hard to tell apart in the shops (and not always correctly labeled), whether it will grow to 5" or 10".

My rule for size of fish vs tank is 4L x 2L x 2L as a minimum - I will not (knowingly) buy fish that may grow longer than half the shortest side of the tank or a quarter of the longest side of the tank. Most of my fish are much smaller than that, but it's the maximum I allow. For very active fish, you need a bigger tank.

--
Mats

Great news ive got my 4 footer today, ive just set up and im leaving it running for 6 to 8 weeks... im not sure what fish to keep yet so can sum 1 please close this topic as im not going to be keeping fish until the 6 to 8 weeks are up... thanks for all replies people xox

While agree with you on the size of these fish, there are a couple of species available in the trade that only grow to around 5-6"/13-15cm such as Geophagus parnaibae (formerly known as Geophagus sp. "Red Head Tapajos"). Most good aquatic stores should be able to tell the difference between many species.

All large fish such as cichlids are susceptible to hole in the head, however by maintaining a reasonable water quality (meaning no ammonia, nitrite and a fairly low level of nitrate through water changes through regular maintanence) then this shouldn't be a problem.

Interesting, Weidners "South American Earth Eaters" say that this species "barely exceeds the 20cm mark".

And my point about tank size was more to the effect of "a larger tank doesn't need quite so many/large water changes" to keep the nitrates in check (hopefully, with mature and sufficiently large filters, ammonia and nitrite should not register on the test-kits).

--
Mats

I've just found this on www.fishbase.org, Geophagus parnaibae, . This states that Geophagus parnaibae only grows to 7.6cm, however most other sources on the internet and even one of my Baensch atlases states that it grows to around 15m/6".