Please check that your basic water quality  parameters are within acceptable range  which are: Temperature range: 68F –82F,  optimum temperature 75- 78F, Ammonia 0, Nitrites 0, Nitrates 1-10ppm, PH 8.2 – 8.4, Specific gravity 1.022-1.025.

Acclimate your  brittle stars slowly, but do not take more than 30 minutes to complete the procedure.   Check temperature and PH upon arrival in both the shipping water and in the tank.  Follow  this procedure :

1.  Float the bag in your tank  for about 10 minutes to equalize temperatures.
2.  Partially open the bag and  add 1 cup of tank water.  (Do NOT aerate the shipping bag during acclimation)
3.  Wait 10 minutes.
4.  Remove 1 cup of water and add  another  cup of water from the tank.
5.  Wait 10 minutes.
6.  Repeat this procedure again.
7.  Gently use your hand to transfer the seahorses into the tank, discarding the water left in the bag. 

Your brittle stars are agressive scavengers. They should not be placed with seahorses.