Observation of Dollar Sunfish Nest building

Well I have fry now. Thursday morning I noticed one of the females was noticeably thinner and figured they were starting to spawn. Because of my schedule I couldn't set an watch but by Thursday evening all of the females were thinner and the males didn't seem to be as aggressive towards each other. I decided to siphon a little out of each nest to see what I would get. Naturally I got some mulm and sand so I couldn't tell if I had any eggs or not. Well last night Shawn noticed some wiggling in mulm in the siphoned water. Well this morning I counted 30+ sets of eyes in the bottom. I also noticed 2 of the fry were trying to swim. I figure by tomorrow at this time I will have quite a few fry free swimming.
Now for you learned ones, I have a theory about the dominate male actually learning/mimicing the stones in his nest. The one male of mine is an older wild caught male from the South Carolina Convention. His nest was much smaller but totally filled with larger rocks. The dominate male was tank raised so he built a large hollowed out nest but with no rocks. It wasn't till about 2 - 3 days later that he added the rocks. I can actually see where adding the rocks would give those eggs/fry a better protection from predators than just a smothed out bowl in fine gravel. The eggs down between the rocks would be better protected from predation than the ones in a smooth bowl. Just my theory on the whole thing.


Bill F.

Aren't the eggs adhesive, so that they would stick to the large rocks very soon after being produced by the female? We used to collect small rocks out of pumpkinseed nests in ponds in MA that were completely covered with eggs and hatch them in the lab. My loose thoughts about the rock-laying was that the rocks offered more surface area, a cleaner surface, and were above the sediment so that they would in principle be better oxygenated by any water flow. It's true that they'd be more exposed to predators, but the p-seed males were always hyper-vigilant about guarding their nests with eggs present.

Aren't the eggs adhesive, so that they would stick to the large rocks very soon after being produced by the female? We used to collect small rocks out of pumpkinseed nests in ponds in MA that were completely covered with eggs and hatch them in the lab. My loose thoughts about the rock-laying was that the rocks offered more surface area, a cleaner surface, and were above the sediment so that they would in principle be better oxygenated by any water flow. It's true that they'd be more exposed to predators, but the p-seed males were always hyper-vigilant about guarding their nests with eggs present.

If the eggs are adhesive, it isn't very much. To vacuum the nests all I used was one of the siphon gravel vacs and just lightly went over the bottom of the nests. I have quite a few fry in a container right now.

Bill F.

Bill,

I bet the eggs are adhesive. Either you missed seeing during the 36-h window or the father continued to tail-sweep for some time after eggs were produced resulting embryos being jumbled out of the original exposed surface. That happens a lot with sand and small gravel. A more remote possibility is that only a small number of eggs produced. I still think at least 400 eggs produced per female, even if eggs produced.

I recommend the use of pro-larvae for nest bound sunfish. When they leave the nest but still look nothing like adults, larvae is more appropriate. The term fry for sunfish that have all the spines and rays of an adult, but proportions, especially the head and eyes are not yet adult like. Care requirements vary greatly on my end of sunfish study as a function of developmental stage.

Could you make a photograph of your young eastern dollar sunfish?

Jim

Interesting info thanks.