"Hoplo" is short for Hoplosternum. Hoplosternum belongs to the family Callichthyidae (along with the ever-popular Corydoras). Hoplosternum's closest relatives are in the genera Dianema and Callichthys so I can see why you would draw the similarity. I have seen Callichthys callichthys sold as "hoplo cats".

The most common sp. imported seems to be Hoplosternum thoracatum. This sp. will reach a length of close to 8 inches. It is really difficult to tell the various Hoplosternum spp. apart unless you have really studied them (I have not). There are some (one ?) dwarf spp. in the genera that reach only about three inches.

Whatever spp. they are, care is about the same. Soft water, pH 7 or a little below, caves, sand or small gravel to "root" in, varied diet, and lots of water changes (as per all fish). They are bubblenest spawners (ala Betta splendens). They will build their nest under floating plants or a floating plastic lid from a coffee can. Spawning can be set of with a large water change that drops the tank's temp to about 63F.