There are several forms of the currently undescribed Thorichthys sp. Coatzacoalcos. Here, Matt Clarke, looks at the rarest, the Gold Mixteco.
Common name: Mixteco Gold
Scientific name: Thorichthys sp. "Coatzacoalcos - Gold Mixteco"
Origin: The Coatzacoalcos river system, including the Rio Grande, in Mexico.
Size: Probably around the 12-15cm/5-6" mark for an adult male, with females a little smaller.
Water: Hard, alkaline water should be fine. Don't keep the tank too warm - 24C should be fine. Other Thorichthys are often found in slightly cooler waters.
Diet: Other Thorichthys species feed on aquatic invertebrates, insects and plants and algae.
Aquarium: Thorichthys aren't particularly aggressive for a Central American cichlid, and although they're still not peaceful enough to be kept in a community setting, it is possible to mix them with other fish. Many Thorichthys keepers go for larger livebearers, such as wild-type swordtails, which often occur naturally alongside the cichlids.
Some species, like the Firemouth, T. meeki, are often found in the weedy, muddy margins of rocky rivers and canals, often in very murky water. Add plenty of bogwood and rocks to provide shelter and spawning sites. Aim for a minimum tank size of about 90cm/36" for a pair. Juvenile Thorichthys can be kept in groups without problems.
Breeding: Presumably similar to other members of the genus. A couple of hundred, or so, eggs are laid on a rock, or sometimes a leaf, and are defended by both parents. The offspring remain with the parents for quite a while.
Notes: According to Juan Miguel Artigas Azas who discovered this cichlid, this is one of three geographic varieties of a currently undescribed Thorichthys from the Coatzacoalcos river system in Mexico currently known as T. sp. "Coatzacoalcos". Juan Miguel has 10 years experience with this species and is convinced these are all representatives of a single species, however, others disagree. It would certainly be very wise to call them by the more descriptive names, "Blue Mixteco", "Green Mixteco" and "Gold Mixteco" rather than referring to all of them as "Coatzacoalcos". If the fish later get split into distinct species, at least there will be a record of who's been keeping and breeding what - that gets lost if we call them all "Coatzacoalcos". This gold form is the said to be the least common.
Similar species: If you can't find any of the Mixteco varieties, look out for some of the more unusual species. There are some decent UK-bred affinis around, as well as a few aureus and loads of ellioti. All require much the same care.
Availability: Very rare in the trade in general and an extremely rare find in the UK. These were spotted at Wharf Aquatics in Nottinghamshire.
Price: Around £14 a pair.