I do not like having to make this post, but I hope that it will serve as a word of warning to other keepers of Cichlasoma Meeki - the Firemouth Cichlid.

I'm afraid that, as a result of moving 6 of them, along with 3 Carpintes that were getting terrorised by the spawning pair of Carpintes in tank 9, I have now lost 2 of them to what I believe is pH Shock.

It is now my firm belief that these fish are susceptible to changes in pH more than most other fish that I have kept. The evidence for this is that I have suffered 6 'strange' losses of them now in the last 6 months, each time either after a large water change, or after housing them for the first time in a tank, or after re-housing them. It would appear that any change more than about 0.2 pH per day is quite possibly enough to kill them.

I have, as a matter of policy, never deliberately changed the pH of the water in any tank more than 0.2 points at any point in time and have therefore never knowingly lost fish to pH shock. Recently, however, I was informed by a reputable LFS that the fish could be acclimatised over a few hours by mixing the water gradually. This does not appear to be the case with Meeki, as I have now found to my cost (and theirs - more to the point).

My (unsubstantiated) suggestion is therefore as follows:-

Always test the pH of the tank water prior to a water change of more than 30% using a narrow range test kit, and check the pH again at intervals during the change to ensure that the pH does not change by more than 0.2

Never rely on a pH test immediately after adding pH UP or pH DOWN, as the change in pH is short-lived. I suggest that waiting an hour or more before re-checking, but this is untested as yet.

If moving Meeki from one tank to another, ensure that the water pH is stable and the same as the water in their current tank. If newly purchased from a shop, test the pH of the water using your own test kit, and adjust the water in the quarantine tank as necessary before releasing the fish.

Do not rely on results that other people have given you for the pH of the water as test kits are slightly subjective and, more importantly, give different results between manufacturers - sometimes very different.

Although these suggestions apply particularly to Meeki, it is good practise, if at all possible to follow them for all your fish especially as pH shock does not seem to register as a concern with a lot of aquarists. If I obtain fish from outside my local area, I apply the same policy to the water hardness, ensuring that this does not change more than 1 dH per day. I have never seen anything to concur with this idea, but it makes good sense to me, especially as the water locally is 5dH and the water from the Jurassic limestone belt across central England is 20+ dH.

Any comments or questions on my thoughts would be gratefully received.