Do Honeycomb Catfish Squeak?

[BrynnaCC]

I have eleven honeycomb catfish in a 40 gallon breeder that sits by my bed. Lately, at night, I've been hearing odd grunting noises coming from the tank. At first, I thought that maybe they were scraping their fins against the acrylic, but I looked in the tank last night during one of the sounds, and two of my males were having a spat nowhere near the sides of the aquarium. Has anyone else experienced this? The sound is similar to that of talking catfish, albeit quieter, but I can't seem to find any info on them doing it.

[bekateen]

Perhaps you're hearing the sounds of pectoral fins scraping/clicking?

[BrynnaCC]

I thought it might be fins scraping, but the moment I caught them making the sound, they were in a T position (one had the other's fin in its mouth). It's not really a click sound. It's more like an "enh, enh" sound (apologies for the less than scientific onomatopoeia).

[Lycosid]

Many catfish do appear to be capable of producing swim-bladder noises as well as pectoral fin noises. The pectoral fin noises can include stridulation where a bone is rubbed across a series of ridges or bumps on another bone. This is the same way crickets and cicadas produce noises. Neither of those sound much like a click and they also don't sound much like each other, suggesting that stridulation can give you a pretty big range of noises. I would guess that the "enh" is stridulatory, and if it's involved in antagonistic interactions it may be a threat sound, a way of saying, "Hey, listen to how deep this noise is - I've got enormous pectoral spines." If it were swim-bladder produced I'd expect it to sound more like a drum or other air-filled object being vibrated.

[panaque]

Yes I've noticed this too. When you shine a torch into a female's cave to check on a brood they often make that sound.