what fishes don't do well with what meds.


Staff member
RC Mod
Copper: things copper may kill ---which is why copper for ich is for your QT only.,
invertebrates of all sorts
live rock bacteria
angel fish
dragonets: mandarin, scooter blenny, etc.
eels are iffy.

generally safe in-tank treatment for flukes, which it agitates into convulsions and causes to die. However, it will kill oif many or all of your bristleworms, and other beneficial life. If you have a lot of them it could spike ammonia.

Wrasses may react poorly to Prazi, especially if weakened by flukes.

Hypo (do this in a qt tank) combats ich by lowering the salinity, which is ok with fishes, not with other creatures in your display tank. QT only.

Cupromine (a copper preparation.)
Drug interaction with:
Cupramine: from Seachem
Q: I've been dosing with Cupramine™ and then I added Product X and everything died. What happened?

A: If Product X is a reducing agent such as ParaGuard™ (or other aldehyde based medications), or if you overdose with a dechlorinator, such as Prime® then the Cu+2 will be reduced to Cu+. Cu+ is 10 times more toxic than Cu+2.
Now this is for cupramine but the reaction should be the same for any copper containing additive I would think.
Cupramine: do not combine with hyposalinity treatment. Do not have carbon in your filter while using. And an auto-topoff unit in the hospital tank is a very good thing where dosing copper, particularly with sensitive species, so your levels of this med do not fluctuate due to evaporation. Not indicated for: angels.
Metronidazole: very rough on some species if dissolved in water. Good where you have no clue whether it's fungal or bacterial or even parasitic, but this is very difficult to dose properly. Food soaked in this antibiotic is probably best and gentlest, administered in a hospital tank.

Finally---anything you do to mass-kill anything from weeds to parasites, worms, aiptasia---if you are heavily infested the dieoff can throw way too much die-off into your tank for it to process: ammonia spike.

Michael Hoaster

Registered Seaweedist
Premium Member
What would we do without you, Sk8r! You've posted so many helpful threads and posts. I've benefitted from many of them. Thank you for sharing your vast knowledge! Chapeau!


Staff member
RC Mod
Thank you ever so much! ;) I've learned some of this the hard way, but a lot of it from other people who just what they learned the hard way---and then there's the companies who do due diligence and test things and post what they learn, may their tribe increase! and the marine researchers. When I started this, we were lucky to keep green star polyp and palythoas alive, and now we're breeding marine fishes and keeping acroporas. So much we've learned. And hobbyists: a number of RC folk contributed their knowledge in composing this list. It regularly lives in the Fish Disease forum, but where do we MOST need it? Where the new folk are, for sure!
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