Thanks for all the replies so far, with some good points and reasoning !
Roy,
So many other factors come into play, beyond just the "inch per gallon" silliness.
Primary concern should be - are the tank inhabitants compatible with each other? Stress is a very big deal to marine fish and will significantly impact their lifespan and your (and their) enjoyment of your tank. Too many fish cause territorial or aggression issues, which lead to stress, which leads to dead fish. And so on.
Some fish are not reef safe. Some are. If you intend to have coral then they should be reef compatible, or some of your fish may eat your coral. Or some may eat other tank inhabitants (inverts) or be eaten by other tank inhabitants.
The needs, habits and personalities can be highly different even between the same families or types of fish. For example - I keep a butterfly fish in my RSM250 that is also a reef tank. Butterflyfish eat coral. Except for one specific family of butterflyfish of which there are four members. Mine - a burgess butterflyfish, is the smaller one of the four and even then the RSM250 barely meets the minimum tank requirements. The burgess is still reef compatible with caution and he has snacked on some coral on occasion. So I feed heavily to keep that in check. My nitrates are not, and never will be, zero as a result. A choice that I had to make when choosing that fish for my tank.
I also keep a tang - a yellow eye kole tang. Again one of the smallest tangs, with a very different personality (very docile) when compared to other tangs. The tank is once again at the minimum recommended size for the fish. (The tang police are now going to be knocking at my door). I push it even further having the burgess and the tang in the same tank, as they are similar in size. Both were introduced to the tank at the same time to try to help minimize thus is issue, and I had a plan going into the decision on who would stay and who would go if they did not get along at any point.
Sort of a long way to say - my recommendation is to be highly selective in what and how you stock your tank. Research, then research, and research again. Try to avoid the impulse purchase of a fish. And quarantine any new arrival.
The surface area of your live rock is only part of the population of nitrifying bacteria. Top quality live rock is highly porous and houses a tremendous amount of the biological filtration inside the rock in addition to what is on the surface. It's why some live rock is very expensive and some is still expensive but half or a third of the cost.
I've never kept chromis, but unfortunately I do not think you will have four for too long. Also, depending on what those 11 fish are, you may find that population self-selects down to a more tank size appropriate number over time. It just may not be the fish that you want that you end up with long term.
Hopefully this is helpful.
Thanks New, I agree with many of your points, although the experience here is very lacking.
All the fish are reef safe as far as we could establish before buying them.
Our fish currently are as follows and given in the order they went into the display tank.
Pair of Clowns
Male Blue Damsel
Dottyback
Blue Tang
Yellow Tang
Royal Gramma
4 Blue Chromis
We introduced each fish one at a time and took care to watch how each got on with and reacted to each other.
The Male Blue Damsel was the 3rd fish and we worried about him accepting the next fish in the tank.
Ready to react we then introduced the Blue Tang, but no issues at all, except for a bit of chasing around for the first few minutes.
The Yellow Tang was the next one to go in. No reaction from any of the resident fish except from the rock algae which had a collective heart attack ..... HeHe
Then the Royal Gramma went in and found his own cave in a few minutes.
Certainly the Dottyback and the Royal Gramma are not best pals but apart from the Gramma showing the size of his mouth they seem to be ok.
Last were the 4 Blue Chromis, we wanted these and that number so they would shoal together.
Reading about a dominant Chromis killing his like, I operated a more defined strategy here.
They were in the QT together for 3 weeks, then they went all together into the DT.
Because of their size I thought the other fish would certainly have a go at them and that happened immediately.
The Clowns were the worst followed by the Damsel and the Blue Tang. No reaction from other fish.
They were chased around, on and off, for about 4/5 days, but they are so quick no harm came to them and they always swam away as a shoal.
The situation is pretty settled and I don't see any dominant activity among them.
They feed out of my fingers with the other fish, they spend the night as a group near the left pump outlet.
Maybe the scene will change but as I watch them right now they are in a shoal all swimming gently against the MP40 current flow.
So what are symptoms of a fish being stressed that we should look out for which may not be apparent to newbies in this hobby ? [We are only just 86 days into this great adventure]
Roy
Here is a photo of our C-250 taken this evening:-