Ok when they are small..... feed at least 3 times a day.
remember brackish tanks tkae a long time to cycle and that adding salt to a
tank can wipe out your good freshwater filter bacteria.
Mono's die like flies in nitrite spikes.
give them some scat friends, they are more chilled in company.
Don't worry too much about slow acclimatisation (salt to fresh to salt to
brackish), in that way at least they are tough.
Get surface disturbance happening to keep tankwater full of oxygen.