Hi jippy, not sure about the company thing because I never have had only one but if you have more than one they should all have a similar size. if you put a young one (up to 10cm) together with adult ones in no time the juvenile will be gone.
ground with fine, roundish sand (not sharp sand) or pebbles big enough so the Axos can't swallow them. they suck their food in and if the pebbles are too small they suck them in as well which can block their digestive system and they will slowly die. to have only a blank glass bottom is not recommended as it will build a layer of algae on the glass which can harm the Axos. lots of hiding places (clay tubes or half clay plant pots, nothing they can move and get squeezed under it). sturdy plants which they use to rest in when they swimm around and use to spawn.
filter which create no or as low current as possible. I use external bucket filter and the return pipe is along the back of the whole tank lenght with little holes.
no bright tank illumination, they don't like it bright, they prefer it dusk or dawn (no direct sun light to the tank). cold water between 14 and 18 degrees C. hard water, if you use rain water put some coral sand in. absolute no chemicals as in water enhancer or clearer.
no mammal meet (no ox heart and such as often recommended on TradeMe) they will not digest it properly and it will start to rot in their intestines. chicken heart if nothing else is available but not more than once a week, best is all sorts of wurms out of the garden (if possible not from the compost or wurm farm unless you feed the wurms only with grass and other natural stuff but not coffee and all the other stuff people put into a wurm farm), grass grubs, crickets, maggots, little fish (guppies), shrimps, boiled fish pieces, flies, mayflies, stoneflies and all sorts of nymphs. the more variety the better.
I fill my tanks always to 3/4 hight so they have enough to swimm but not enough to jump out. even if they look lazy and slow if they are in to it they will be very, very fast.