Hi
antennata are less hardy than volitans, but once acclimated do very well. I' have a pair that over 3yrs old (about 7-10" including tail). If you get a small antennata expect it to outgrow this 30gal tank in under 8 months.
These fish grow slower than volitans, but faster than many fish. If you do get a lion remember than you cannot add any fish/invert which could possibly fit into the lions mouth,it will be food.
The only other thing you need to know w/ lions is you have to ween them over to dead prepared marine flesh. You really can't feed FW feeders fish to them long term, its not good for them. Actually ghost shrimp is a decent FW food to start. Once they are used to eating and happy in your tank, ween them over. Some excellent foods are shrimp chunks(w/ shell),scallops, crab, silversides, etc, you can get all of these in the fresh fish section of your gorcery store. Skip the freezedried krill, and cooked shrimp chunks/
Actually what i would be more concerned w/ is, w/ your small volume of water will you have decent water quality after feeding meaty foods to this fish.
My personal opinion is this tank is too small for this fish.
As a possible alternative to an antennata consider some of the dwarf lion species (dwarf lion, dwarf fuzzy lion, and fu man chu lion). All will stay under 7" , and grow slower. Dwarf fuzzies might be a good choice.
Feel free to check out my lion collection under my name
frank
frank