PlanetCatfish.com

I have an L-204 occupying a cave and recently a second one has been hovering on top/next to the cave.

Both fish are about 5.5" (14cm)and look well conditioned.

When looking at them for sexual differences I notice the following:

The one occupying the cave seems slightly fatter and rounder, it also appears to have more furlike growth (odontoidal) on the rear of its body.

THe one hovering near the cave is slightly slimmer with less odontoidal growth on the body - almost smooth.

Both fish seem to have identical odontoid growth on the pectoral fins and "sideburns"

The fish in the cave is slightly paler while the other is very nice and dark (I think this may just be due to hanging in the cave)

The behaviour however is as follows:
The one in the cave has always kept in or near the cave while the other has stayed under and around a root at the other end of the tank. We recently had rainy weather move it and at that point the one from the root went and checked out every cave in the tank and finally settled near the one occupied by the other one.

I'm puzzled by the fact that the one in the cave that I presume is male seems fatter and rounder while the other one is slim - yet the one in the cave seems to have slightly more odontoidal growth but only on the body.

Is there anything else I can look for as a giveaway for sexing them and are the differences as vague as it appears to me?

I've had the fish for about 2 years and they have always been together , they have been in this tank for about a year and this is the first time I see this behaviour for an extended time.
Thanks

Males and females have similar odontodal growth on the pectoral fin and cheek but the males cheek odontodes is longer and thicker, females lack (extremely short) body odontodes and males have quite heavy of them and cant be missed.
L204 as many other Panaque species dont show so much interest in caves except under breeding period when usually the male occupy what he thinks are the most suitable cave, one interesting behavior that L204 have is that the male can be laying in the cave with his long filaments sticking outside the entrance and when the female makes a visite she use her filaments to touch the males...they can lay like that a very long time and taste each other.

Janne

This is a picture - the one in the cave has been occupying it for a while while the other just moved in during the recent weeks (3) and has been keeping nearby for the most part over that time.

The most apparent sexual dimorphism is these Panaque is the amount of odontodal growth on the caudal peduncle.

when you have a mature male, it's unmistakeable.

My L002 only developed this once i had softened the water quite considerably though, or maybe a coincidence?

OK,
racol, excuse my ignorance but what is the caudal peduncle?

I did a big waterchange yesterday (60%) and used part RO and part cold tap. This dropped the temp by about 8 deg and lowered the TDS from around 300 to about 190. Not very soft but a good difference.

The problem is that the tank is 125g (500 litres) so it is hard to do a big RO change.

This is another reason that it has become evident that something seems to be going on.
For over a year the male has either occupied or stayed around his cave on the very right side - near the glass while the other one has stayed under a root on the very left side. The tank is 6 feet 1.5 meters and the fish have kept that distance. Now all of the sudden for the first time the one from the root is totally hanging out near the others cave (there are several other caves to choose from if it was just to get a cav e).

Note - after the waterchange the one from the outside got really close to the opening of the cave where the first one waved his tail and stuck it's nose into the cave a few times. There was no real interaction (hostile or other). The pleco from the cave sortof moved aside a little and let the other one sniff in there.

After a short while the one sniffing moved away and settled just outside the cave.

I figured I would provide a play-by-play just in case something does happen.

The caudal peduncle is the "wrist" of the tail, just before the body turns into the tail. The odontodal growth looks like lots of small barbs or hooks in this area.

Here's a pic of a Panaque albomaculatus (a very similar fish to the L204) showing the hairy growth.




At the size your fish are, i would expect you to be able sex them. Try and get some close up shots of this area.

Sounds like the one in the cave is male though.

I can't really help you with breeding behaviour side of things though, as i've not bred these fish.

good luck!