Rotifers I understand but brine shrimps?
You can buy brine shrimps eggs in any peatland/petco store and hatch them in about 24-30 hours in water from your tank or fresh salt mix...
(even kitchen salt is fine but not iodinated)
All you gonna need is empty 2l plastic bottle, small air pump to move the eggs, one vial of brine shrimp eggs ($4-$5) and patience
30 hours and you gonna have your own fresh brine shrimps...
GL with clown babies!