Trumpet knives and elephants........ well I never!

[Fishman Dave]

Probably not deep enough for either the knives or the elephant nose. I have sand to probably only a quarter inch deep.
Not found much info at all on trumpet knife but I am assuming you either think they may bury in sand a little like rays? Or use the snout for feeding in the sand?

 

[kno4te]

Probably not deep enough for either the knives or the elephant nose. I have sand to probably only a quarter inch deep.
Not found much info at all on trumpet knife but I am assuming you either think they may bury in sand a little like rays? Or use the snout for feeding in the sand?

I assume they are using their mouths for feeding in the sand. Not sure about burying. Seen some thermometer knives do it. Have you seen any behavior of that mentioned?

 

[Fishman Dave]

Not yet, but to be honest I went a little overboard with the flat rocks, bog wood and branches and there is very little of the bottom of the tank really open. Still plenty of places for them to delve but just thinking about it, most of those places are round the back, front and side glass panels where in this tank there is a strengthening glass rim round the bottom so the sand is not so deep. Want to get hold of some live bloodworm or tiny earth worms to really see how they eat. Tank has lots of trumpet snails so also wondering if they are eating those too. The placement of their tank doesn’t make viewing easy as it’s on the floor of my fish house on the entrance and really want to spend a little time this week laid watching them (not so easy when I have tanks crammed into every available space).

 

[fishhead0103666]

First post, Gnathonemus petersii I believe.

Sorry about that, I’m not sure how I missed that.

I’ve heard that they’re quite aggressive with their own kind unless you have like a group of 8+, do you have any plans if any aggression starts to be shown?

 

[Fishman Dave]

I do plan to upgrade in a while to another grow on 350 ltr before moving to one of the six ft tanks later but for now I do have options where each could go if really pushed, just that they wouldn’t be an ideal tank mate. There is aggression there already, but that much bog wood, branches rocks and java fern that anything dissipates very quickly. Amazingly (for an electric pulse emitting fish) out of sight seems to be out of mind. And I often see one stop chasing another when he goes round a java fern plant and the two end up simply being at the opposite side to each other with a knife in the middle. That’s why I only went for three as I felt the four foot wouldn’t hold any more and give them room to get out of each other’s way. That and the six foot ear marked as longer term home for them is not free till the variagated hemibagrus gets big enough to risk going in the pond, and that could be 9 month away yet.

 

[Fishman Dave]

Tonight I managed to get a little time to watch the trumpet knife fish and elephant nose feeding on frozen bloodworm.

The trumpet knives use their snout like a vacuum, hoovering up the bits they find and probing under the edges of rocks etc, whereas the mormyrid use theirs as a sensor, checking if something is food before tilting and picking it up. Still not seen either actually probing in the sand.

 

[kno4te]

Seems to be adjusting well. Looks like it’s doesn’t need to get into the sand. Maybe a suggestion. Bury the bloodworms into the sand and see it’s behavior.

 

[EntoStentor]

Seems to be adjusting well. Looks like it’s doesn’t need to get into the sand. Maybe a suggestion. Bury the bloodworms into the sand and see it’s behavior.

ooh, that would be interesting. Also an opportunity to see how good their sense of smell is.

 

[Fishman Dave]

Well, things have changed a little. Whilst the arowana was in the tank the elephants were all model citizen's, not really squabbling but staying away from each other, but now that I moved him out, one just took over. Patrolling the whole tank trying to find the others. I now have just the one in the tank and the not so ideal other accommodation has become individual homes to the others for now. Really thought that a 4ft tank would be enough space with that many rocks and wood for them to get on but this one fish is a real explorer, out with the lights on all the time in and out of rock work and woodwork always testing any crevice or sand patch with his nose. Not sure he was actively looking for the others but when he found them he would just chase them into hiding again, so much so that they were not eating. Thankfully he completely ignores the trumpet knives but he does seem to think he is a hoplo catfish, happily rooting through the sand with them.