Apisto orgies

[Bart Hazes]

In the past month I have had at least 8 spawnings and often they came in pairs, either simultaneously or within a few days. Two A. ortegai in one tank, two A. rubrolineata in another and two Dicrossus filamentosus spawnings in a third. Today I had an A. macmasteri pair spawning but then noticed an A. rubrolineata pair were also going in/out a second coconut and if not spawning then at least engaging in foreplay.
I've heard people say hormones released during spawning can stimulate other fish to spawn. How common is this and is it normally working for fish of the same species, as I observed twice, or also for different species as with the macmasteri and rubrolineata.
Interestingly, I am 99% sure that I twice saw a small A. rubrolineata, presumably the small male, enter the coconut with the female A. macmasteri. More surprisingly, she did not immediately chase him out. He is kept from breeding with the A. rubrolineata females by two larger rubrolineata males, so perhaps he was trying to sneak in some sperm under the radar. Macs and rubros are sufficiently different that I would be very surprised if hybrids were viable but if I get weird offspring it would prove the observation.

Here is the macmasteri male entering the coconut to do his manly duties.

 

[Mike Wise]

There is no scientific studies/proof of hormone induced group spawns in apistos. It's more likely that water quality/conditions, tank maintenance and food coincided to induce simultaneous spawns. It happen to me often in separate breeding tanks. As for hybridization in apistos, this should be very rare if there are both sexes of the same species in the tank. If not, well ... 'any port in a storm'.

 

[gerald]

Shiners (Notropis, Luxilus, Lythrurus) and Dace (Chrosomus, Clinostomus) that spawn on Chub nests (Nocomis, Semotilus) in eastern USA are apparently attracted to spawn partly by the smell and/or sight of the Chubs spawning. Smell and sight (plus a feast of chub eggs) might stimulate breeding hormones in the Shiners and Dace regardless of whether any hormones are actually released into the water from the Chubs.

 

[Bart Hazes]

In recent weeks I observed two apisto spawnings. An A. norberti I got to see from start to finish and for A. macmasteri I saw the middle and end part. I may have seen parts of an A. rubrolineata spawning as well but can't be sure unless I see fry in 9 days from now.

For the norberti the female stayed inside a coconut cave for half an hour. She had closed of the entrance with a pile of sand so the male could not enter but he passed by on occasion, turning his vent to the cave opening and finned with his pectorals presumably to force sperm into the cave. As the female deposits eggs she has to trust the male to stop by to release sperm in time. In the period leading up to the spawning he certainly did not do that. I was wondering if release of eggs and sperm was solely a timed event, with the male ejaculating about once a minute without knowing what happened inside the cave and female depositing eggs without knowing what the male was doing or if there are audible or chemical signals being exchanged to ensure both fish do their parts. The norberti female took almost 24 hours of foreplay, the female taking the active role wooing the male, before the male became a reliable partner and spawning ensued. I was surprised the male would not be more eager to spawn, since 'sperm is cheap'. Maybe if harems get big enough sperm becomes a more limiting commodity.

For the macmasteri I didn't see the start but I don't think they have the long period of working up to a spawning. The female also did not close off the opening to the spawning cave and remained in visual contact with the male, often poking her head out and tilting her belly towards the male to catch his attention. The male would then completely enter the cave for about 10 seconds and come back out. A. rubrolineata behaves more like macmasteri with the female not closing off the cave and the male entering the cave for fertilization. For these species visual cues and actual presence of both partners in the cave can ensure release of gametes by both partners occurs. From earlier observations I also recall that for these species both the male and female take an active role in wooing the other sex.