Mormyrids and Synodontids

[stormhawk]

In response to Wayne's experiences with the mormyrids, yes I understand many do not make it in beginner's tanks due to the lack of live foods. I've never had a mormyrid before because for a reason, they give off an electric field when stressed that can cause some discomfort in the other fishes. Therefore I decided not to. When looking at the fish in the shops, I get very interested but stop when I check up how big they get. Wayne, you have a large species there in the tamandua. I know the Baby Whales are cute, saw one for sale in a tiny container at a very well-known shop. Pretty tough environment for a cute fish but nonetheless, they make very interesting aquarium subjects.

As for the Synodontis, yes, the most common species in the market is the eupterus, or sailfin syno, but i've seen some beautiful species like S. polli for sale locally. Beautiful white-rimmed fins. When I first obtained my eupterus, I had originally thought these were Synodontis nigriventris or contractus, but it seems these are very uncommon locally.

[Slaigar]

Synodontis polli is a beautiful fish. Personally though, I would not be able to identify if shown S. multipunctatus, S. petricola, and S. polli together. Even with similar appearance, S. polli seems quite more expensive than the others(atleast in North America). One day, I am going to buy a shoal of one of these to breed .

Mormyrids are quite interesting fish. I have heard not to mix species together in small tanks because they are territorial. They will be able to track each other down with their electrical signals Also means not to mix them with knifefish. But I have no first hand experience, I hope someone on the board can shed some light.

[tumorgenic_fish]

I have a number of mormyrids alongside Synodontis in a 5ft x 2ft x 2ft tank and they are the only kind of fish I have in my tank.

The mormyrids in my tank include, Gnathonemus petersii, Pollimyrus isidori,Gnathonemus tamandua and some which I am unable to identify.
I never mix knifefish (another of those eletric fish) with them (don't like the look of knifefish), so I can't really comment about knifefish and elephant noses compability.

About aggression among mormyrids, I got 7 Gnathonemus petersii in my tank. All of them smilar in size (about.. 8-9cm?) When I first got 3 petersii , there was one particular petersii which seem to be overdosed on testerone (if there is such a thing in fish) and kept stalking the other petersii non-stop until it put them all place! The aggression stopped when I raised the number of petersii in my tank and added other mormyrids.

Tamandua don't seem to be agressive ( I got 3, they are about..roughly slightly less than double the size of my petersii), The baby whales (got 5 of them) used to take pot shots at the petersii and my syno eureptus all the time but they stopped after a while.

Re-arranging the tank decor might cause the nonsense to start again, now that peace has prevailed and terrotries established I don't want to ruin it by having the decor to my liking but not to the fish.

As other fish being bothered by these 'electrical signals' some of my synodontis seem to rest side by side the mormyrids. I have a feeling that over time these fish learn to recognise the 'electrical patterns' of the mormyrids and learn not to be bother my them. In anycase, my synos do not seem to react negatively by when they glance past them. You definitely will not get 'zap' touching an elephant nose.

One very interesting thing, I observed some of my petersii will actively seek out their particular synos in the tank for company during resting. It seems to me they can recognise their syno buddies somehow. Maybe by electric signature? No idea. These particular petersii will also respond to the dithering effect of their particular syno buddies. (i.e if their syno buddy move to the other end of the tank they will follow)not all my mormyrids do that. As for the baby whales.. hmm.. they well.. behave like.. fish Not as interesting as petersii. The tamandua seem to keep to themselves. Mine at least don't seem to chase the other mormyrids or synos when they venture too near them.

During bouts of agression, I don't think any real damage is done. Their mouths don't seem capable to do any damage anyway. They just seem to just engage in bumping. Lots of bark no bite kindda of thing.

The mormyrids seem to grow very very slowly. The only difference I see in them is getting fatter or thinner. I did mention that some will take dry food after a long time, I should qualified by stating, that mine at least only take freeze dry bloodworms and freeze fry daphnia. They leave those freeze dry tubifex worm cubes alone. Mine will absolutely not take things like tetra bits sinking pellets bits, flakes (sunken or floating) or similar stuff. They will self-strave if they don't get what they want. I think it is their mouth structure. They can't exactly 'tear up' or chew food. They slurp them up. (No not through their 'trunks', their trunks appear to be their lower lips their mouths are located above them) The mormyrids are also good jumpers. I lost a few before till I got a plastic mesh to cover the tank.

My tank parameters. pH 6.8, temp 28 degrees celcius, ammonia + nitrite 0 and Nitrate about 25mg/L. ADA africana aqua soil for maintaining pH and I use gravel to cover the soil. It was messy with just ADA aquasoil alone at the bottom as the synos would make a mess with the soil and the tank would be perpetually cloudy. So, I was forced to cover the soil with gravel. Flora include various types of Anubias. I tie them to driftwood.
Filtration in tank: two Ehiem 2217 (old and messy to work with but haven't bail on me yet).

Most I can share about my personal experience on the mormyrids is mostly observation. How much is just observatorial speculation or true science I wouldn't know.

Cheers,

Wayne U-L