The complete stock list at this point is:
1 3-4" silver Arowana
3 1-2" Spilurum cichlids
5 1-2" Celebes Rainbows
1 1.5" Dwarf Rainbow
2 ~1.5" Julii (I believe- I've had them forever and I can't remember for sure anymore) Corys
1 ~3" Clown plec
Sooo, it's about 27" of fish. The generally accepted rule is 1-2" per
gallon, but just because that's the accepted standard does not mean that it's actually relevant to anything.
My first setup in this tank had a huge number of fish in it... I started out with a few white clouds, fancy guppies, some bronze cories, etc. I also ended up with a couple of goldfish from a science class.
So, it originally had something like 3 2" goldfish, about 30 0.5-1" common guppies (I started off with like 5, but you know how guppies are...) about 4 1.5" or so fancy guppies, 3 or 4 white clouds, 4 bronze cats, and like 8 Otos. I think I had a siamese fighting fish in there, as well, but I can't remember if I took him out later on or not.
Regardless, the tank was certainly overcrowded in terms of the amount of space the fish had, and the goldfish kind of drove everything nuts, but:
-I never had any diseases with that tank
-The plants grew very well, despite the goldfish
-All of the fish appeared healthy- no torn fins, not emaciated, etc.
-They all ate well
The way the tank is now, the plants are growing like crazy (I just pulled out the plants to trim them; some of the stems on one species of the plants I have in there (I'm not sure what it is; it's the broad-leaved thing in the foreground of the attached pic) had grown all the way across the tank and were growing out the hole in the lid where the eheim siphon tube exits the tank. The total length was around 32". In a 10g tank, that's enormous. I ended up cutting them way back and getting rid of a lot of the extra, because I just didn't have room for it. My largest Amazon sword was in excess of 8" in diameter before I pruned it back.
Beyond the fact that the plants are growing very well, the fish are all quite healthy. They eat well, they show no signs of stress, no torn fins, nothing. The cichlids do squabble on occasion, but for the most part, they leave each other alone, and I have never seen them get into a serious fight. They chase each other around a bit, but that about covers it.
So, if the fish aren't showing any signs of stress, they eat very well (including the Arowana), and the plants are happy, I fail to see the problem.
I've kept all sorts of things that people said couldn't be kept in a 10 gallon tank with no problems what-so-ever.
For example, the last setup I had was discus. I tore the tank down a while back, and in the middle of cycling it, I saw 3 baby Turquoise discus that the LFS wanted $19 for. I'd been toying with the idea of keeping discus for a while, and $19 for all 3 of them was a steal, so I bought them.
I finished cycling my tank with Discus. How many did I loose? 1, 2, all 3? Try 0. I've said it before, and I'll say it again. Anyone who has trouble keeping Turquoise Discus is either:
a- An idiot
b- Not willing to provide the attention required, which is no more than any other fish.
I cycled the tank with them, and then I kept them for a few months before deciding that they were getting too big for the tank and that I wanted to try something else. However, for the 6 months or so that I kept them, they grew very well, and they ate everything they were offered, including flakes. I never had a problem getting them to accept the flake food, ever. They never got sick, even when I accidentally left the heater unplugged all night in a 65*F room. No ich after that, no nothing. They were NOT happy about being that cold, but once the tank warmed up again, they were all fine. For all intents and purposes, keeping Discus is no different from and no more difficult than keeping Angelfish, at least in my experience.
I've had baby Angels in there, as well. I've also had a basically full-grown pearl Gourami. I had a fairly small (4") Elephant nose for a while as well, and it was very happy in there.
Basically, my point is that just because something is generally accepted as being something that should not or cannot be done doesn't mean it cannot or should not be done.
So, for right now, it's fine. My siblings have finally gotten interested in aquariums, so I took them to the pet store today and got them set up. There were a couple of things that caught my eye- tiger barbs, checkered barbs, white clouds, neon tetras and guppies, in particular. I've had them all before (except the Tetras), but I may end up selling what's in the tank now (except the catfish) and replace them with a fairly large school (~10-15) of small neons, guppies, white clouds, checkered barbs or tiger barbs...