trying to put together a sticky-worthy Wolf care guide- help required.

[DrDoNothing]

IME care for all of them is the same,except for size and aggression.
in general it'd be:

hardy fish,any pH around neutral is fine.
can be kept with most fish not big or aggressive enough to be a threat,and not small enough to get eaten (except in the case of the aimara,and sometimes other hoplias individuals as well,the erythrinus and hoplerythrinus are usually fine with other species)
except for the hoplerythrinus,they do not enjoy the company of others of the same species (many have had success with several malabaricus kept together,some have ended in failure.)
easy to get off live foods,feed meaty foods like smelt and shrimp,some will take pellets.

size can be frustrating.
often one species will have variations,some getting bigger and some getting smaller.
i can tell you that
erythrinus erythinus usually gets to 8",with some getting to almost 10".
erythrinus sp. peru gets to about 8" as well.
hoplias malabaricus usually get to around 20",but i have seen 24" specimens.
hoplerythrinus unitaeniatus gets to about 16".

Good stuff so far. I've had an erithrynus in a tank as a solitary specimen for about 8 months, so I'm obviously a wolf noob. Here's what I've noticed, however: Mine is in a heavily (fake) planted tank, and never hides in his cave. When there were fewer plants, he would hide all the time. Now, he takes pellets off the surface, and we play a game of catch with sinking carnivore pellets. Very skittish fish, but is also quite territorial. Will take a nip at practically anything that breaks the surface of the water (including net, siphon, or finger). Has quite a hardy appetite for his size, and is extremely tolerant of water conditions (nitrogen cycle especially). This particular individual is completely intolerant of tankmates of any size or species (regardless of his size relative to them, he tries to take them out). He was intolerant of larger or equal-sized fish, including cichlids and catfish, and would of course eat smaller fish a piece at at time. However, this characteristic is likely idiosyncratic. The flash washes out the colors a little bit in the pictures below, so you really can't see his horns or pitchfork very well.