Live feeders are only necessary for fish that are reluctant to pick up dead or artificial food. Seahorse, especially wild caught are especially picky about their food if it's not live.
Most feeder ghost shrimps can be classified into 3 groups.
The true feeder saltwater ghost shrimps does not grow more than an inch usually. and can be kept alive in most marine and brackish water tanks without special needs.
The other kind of salt water feeder shrimps are actually coming from hatcheries, they are the ones that will grow big into tropical table shrimps that are commonly grown in Asian countries. I have been sold some of these shrimps as saltwater ghost shrimps once upon a time, and the largest grew up to 4 inches before it was fed to an moray.
The third group are actually freshwater ghost shrimps commonly found in most pet shops. They are close cousins of the saltwater varieties.
All these shrimps can be great for your fish, but are somewhat pricy. Unless your fish are really picky about if their prey is dead or not, I wouldn't suggest any buying these shrimps. For the same money, you could buy frozen mysis with much much higher nutritional value then any of these live feeders, ounce to ounce.
If you need to keep these shrimps alive, make sure the water is aged (cycled, matured, or stored old water from the tank), the shrimps have plenty to eat (They wouldn't hesitate to cannibalize on their sibblings, if they are really hungry), and the water parameter are kept constant with near zero ammonia and nitrite.
They can be fed nutritial food pellets before you fed them to your seahorses, frogfish....etc.
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Lion fish and other larger carnivore fish can be fed dead fresh seafood easily. Feeding them tiny live feeder shrimps are like dropping dollar bills into an old well........... These larger carnivore fish should not be fed freshwater feeders either.
If you are destined and really believe feeding them live food is better for them, you could buy damsels. Yep, Damsel fish. Or any saltwater fish not in the danger of extinction, are being commercially bred, and their price at sale are really a steal.
I did tried to feed groupers cockroach......... No, it just won't sink................
