[rayjay]

Sorry about my tunnel vision Carol. I'm old and just got to the "northern" and saw seahorses when that part wasn't even there.
I don't know if pipefish are as sensitive to bacteria as seahorses so someone else will chime in on that.
It's not just vibrios but those species are most common.
Best I can say at this time for water quality is to clean the mechanical filtration (sponge or anything else that traps detritus) every 3 or 4 days before it decays to aid bacterial growth.
Also, use a turkey baster or small powerhead to blast the crap from areas it gets trapped around/under rock and decor for removal.
You might be able to get the pipefish on frozen faster if you start to mix a bit of frozen brine in with the live brine (hopefully you can enrich the brine first with something like Dan's Food from seahorsesource.com. As they start to take to it, you increase the amount of frozen and decrease the live until all or mostly all frozen.
If they are large enough to take frozen mysis that's a better food to get them on if possible.