Krib dither in a 20 gallon tall...

Well another of my dither fish was dead when I came in this morning, bringing my total down to (2) zebra danio. One didn’t look so good when I left work last night, and I saw my kribs picking over the remains of one this morning. I am not sure if the kribs actively killed it, if it just died, or more likely, it was weak enough that the kribs could kill it when it ventured too close.

I had been thinking of changing out the danios for a while for something less high speed, and perhaps a little more pretty to look at. One fish my LFS has at a decent price is the Serpae Tetra (Hyphessobrycon callistus). I also was considering the black tetra ( Gymnocorymbus ternetzi) though of the two I like the Serpae better (and it cost slightly less). I would probably add 4 or 5 (and remove the danio).

I was wondering if anyone knew if either of those would be a problem with my two kribs.

Some other quick info…
20 gallon high tank, (see my profile for other tank specs)

The krib pair I have in there was added farily recent, and they have only in the last few days settled down with each other (which probably means I will be having little ones in the future). Both the male and the female krib are only about 2 inches long.

I think the danios had some problems from the begining. The only ones that are left from my original 5 are the ones that had no large marks on them from when they were netted at the lfs by the inexperienced help (which I have learned to avoid now).

I will give the current danio another week or two in the tank to see how they do (as my two healthiest ones are left, which should be a good indication if its something in the tank that is causing their demise).

All test reading on the tank have been good. I lost two danio in the week and half since the kribs were added. One danio died fairly soon after I had gotten him as I was setting up the tank.

I will keep my eye out for them. What I get will depend heavily on what is availble at the LFS.

What I am looking for is a decently colored fish around 2" (or less) in length that has the taller body profile (unlike the danio body). It should be able to withstand and get away from any punishment the kribs can and probably will dish out, occupy the middle to upper parts of the tank, and be able to withstand slightly acidic water. Also I am hopping for something that won't cost too much as they are not to be the focus of the tank, just a nice extra.

I am almost positive now that my previous danio deaths were due to the combination of injuries sustained when they were netted at the pet store, and the inclusion of a more aggressive fish in the tank (the kribs).

The two remaining danios seem to be fine. Checked water parameters again this morning, and everything looks good. I do a weekly 12.5% water change (2.5 gallons) which seems to keep the tank going strong.

I have noticed that previous to the kribs introduction into the tank, the danios were all over the place, and would frequently be near the bottom of the tank, though they obviously seemed to prefer the middle and upper regions. Now most of the time they are in the top 3 inches of water 90% of the time. Occasionally one will swim lower, but if it swims to close to one of the kribs, or too near one of their favorite caves, they will be chased away.

The two danios that are left are the two biggest of my original five, and the biggest of these two was always chasing the other danios around. Now it (not sure on how to sex danios) only has one other danio to chase. I had always heard that they do better in a group, and I am wondering if the diminishing numbers are having an adverse effect on them.

There is always the possibility that the kribs brought some disease in with them, but I havn’t seen any visual sign of disease or problem other then the danios death (and subsequent eating by the kribs).

Well the plot thickens a little.

Came back from lunch to find one of my ottos dead on the floor of the tank. When I pulled its body out, I didn't see any signs that it had been attacked or harassed (though it tail fin was a bit ragged). I remeber seeing this otto earlier not moving attached to the side of some drift wood. Don't remeber seeing this particular one moving today though (it was the biggest of the three I had). The other two appear to be in good shape. There is still a decent bit of brown algae, and some green algae in the tank, plus as a precaution I droped an algae tablet in for them in case it was a food issue.

I am starting to wonder if my test kit may be off, so I am planning on picking up another one today to test the water.