R.I.P.
You have neon tetra and corys so have to be careful with the salt.
I would only add one tablespoon of salt and thats its.
Stir in the salt in a jug of tank water till disolves and add to the tank.
How many gallons is the q tank.
thanks both - thankfully I got home from work this afternoon, and the remaining three are still alive

(at the moment!) - the quarantine tank I'm planning on getting will be about 40L as thats all I have space for right now, but the separated part of the existing tank is about 25L, but any salt I add there would mix through the rest of the tank
I'm seriously considering going out and getting the quarantine tank tonight, but I'd need to cycle it etc. first so that wouldn't be much good - or, could I just transfer 20L of my main tank water and add 20L new water, add a heater and leave it unfiltered for a few days (a lot of websites say ADF's dont necessarily need a filter?), in which case I could have my frog quarantine tank setup in a few hours from now! (as I said, I'd much rather avoid mixing salt in with the fish if at all possible!)
edit: my thought was it could be a bad batch from the LFS - seems odd for this many to die in a day or two, plus a frog I've had for a few weeks to suddenly die overnight! At least the LFS will replace the frogs, although I can only get two replaced because I've buried the other two - I doubt the shop want exhumed frog bodies taken back

I'll be keeping the latest dead frogs though - all my pets deserve a proper burial, not being thrown in the bin at LFS!!
thanks
