You could grow your own brine shrimp in a hatchery and feed them to a variety of tropicals. Any food fish or inverts you grow will have to be done in a seperate tank. Fish are glutons and will eat everything in sight. In a planted tank you will find that small pond snails come with the plants ( unless the plants are hygroponically grown). Clown Loaches love these snails, but you really wont observe them eating them except for empty snail shells once in a while in the gravel. Unless I am missing something, I can't think of much else to do in a habitat as small as most home fresh water aquariums. Or you could go with a reef tank. That is my next project when my home is done being built and we are settled in to the point I can handle it.

what type of invertebrates are you thinking of. An aquarium is not nature and as woeisome suggest you will need a continious supply. frankly I hate feeding live things of a certain size to my fish (I grow my own worms, brine shrimps or feed frozen) so hoping you don't mean the interesting hobby of crabs, lobsters and shrimps (larger species not brine) so on that some raise as they are interesting in their own right.

I realize having a background in pre vet studies that this is all part of nature, be eaten or eat, but as was discussed on practical fish keeping magazine, unaware to many, that youtube now features those who like those who sponser dogfights so on, it has become a sport and rather cruel in some instances. (putting spikes in lips of oscars and chilids so they can fight to the death, tying live mice over aquarium until piranahs jump up to slowly nip it to death). I am not saying you are suggestion this. But not sure from your message exactly what types of invets?

So get a tank full of predatory type fish, raise your own worms so on (google and you will come up with starter kits, grindle, meal so on) and feed them. I keep in my container full of prefilter water snails, so I have an endless supply to feed my fish on occasion, smash, rince a bit while holding and they come a running, lol. (always grow your own, some carry disease, and I saw a guy at local pet store with missing finger from smashing snails in the shop - ikes!)

Putting the two together in a small system that is not nature (ie no continious natural supply of insects/worms/snails/crustations (forgive my spelling) so on and having to hunt for them which uses energy up, and competition from all other fish in the area) means they will eat them up in one setting, (which can get expensive if you mean the larger species) and this can lead to disease and or death. (not to mention one messy tank, lol)

So sorry not sure exactly what type of system you are thinking of...small things like snails and worms which can grow in gravel, so on, or larger inverts? Best Sherry