Would be nice to know if they are from ORA. IME most wholesalers don't like to talk about that kinda stuff though.
Many of the seahorses being imported are raised in ocen pens. Over the past year or two we have seen a large number of these seahorses experience problems.
Common symptoms are stringy white poop, and the loss of weight or the inability to gain weight.
The parasites usually present themselves in the intestinal wall, gas bladder, and gills. Once they are established it is often hard to rid a seahorse of them.
With parasites there is never an exact time line, but IMO, since you do not know the origin of the seahorses I would prophylatically treat them for parasites. It's not an antibiotic so it is fairly safe and will not have future risks. It's something we suggest doing with all WC seahorses.
I'd do a 10 minute fresh water dip matching pH, and temp. Easiest way IME is to do it in a 5g bucket or so. I add an airstone and something for the seahorse to hitch to. If the seahorse lays on the bottom of the bucket, and looks like it is in distress, I would discontinue the treatment. If the seahorse is thrashing about, but not laying flat, keep it going. It's kinda painful to watch.
I'd follow with a round of treatments of Praziquantel.
Since your a science teacher you probably have a microscope? You can take slides of there poop to look for the parasites. They are quite disgusting looking.
There is some experimenting with some other medications going on to see of there are some that are more effective against particular parasites that seem to be more resistant to the praziquantel. Right now we're kinda stuck there.
HTH
