Sometimes wonder where bladder snails come from...

[GaryE]

A couple of club members said they were putting snails in with their Cory eggs, because the snails ate only infertile eggs and left the good ones alone. I was very skeptical, because I'm a snail disliker. I thought they were absolute egg predators.

I wasn't breeding Corys then, but I had a lot of killies. I collected eggs and put them into petrie dishes where I had installed bladder or trumpet snails. There were a few dishes with each. I had waited til the killie eggs showed the first dark spot, proof they were fertile. Their incubation period is an average of 14 days total. Since Corys are quicker to hatch, and I didn't want starvation from the snails to trigger desperation eating, I gave then 2 days or so. I wasn't being super scientific, just curious.
All the eggs in with pond snails were eaten. One egg in with the ramshorns was, over maybe a dozen in 3 dishes. I may have misjudged its fertility.

My Cory breeder friends were more rigorous, and they repeated their experiment with Corydoras aeneus several times. They wanted something solid they could make a presentation to our club with, so they gathered more data.

Their result was different - the pond snails didn't eat the majority of the eggs. The ramshorns ate none, like with my killies, and they decided to only use ramshorns in their incubation trays. The fact most of their eggs survived the bladder snails may be due to the eggs. We look at them as objects, but they're alive. Some fish eggs have chemical defences against their predators, and maybe the Cory eggs had better chemicals than the killies. That's pure guessing.

Someone with the right laboratory tools and time on their hands could play with that one, and maybe learn a lot more. My conclusion is that bladders must burst. I squish them if they're small (the fish eat them) or introduce them to my turtle if I can pick them up. Ramshorns get to thrive, as they are also good indicators of overfeeding.

 

[AdoraBelle Dearheart]

A couple of club members said they were putting snails in with their Cory eggs, because the snails ate only infertile eggs and left the good ones alone. I was very skeptical, because I'm a snail disliker. I thought they were absolute egg predators.

I wasn't breeding Corys then, but I had a lot of killies. I collected eggs and put them into petrie dishes where I had installed bladder or trumpet snails. There were a few dishes with each. I had waited til the killie eggs showed the first dark spot, proof they were fertile. Their incubation period is an average of 14 days total. Since Corys are quicker to hatch, and I didn't want starvation from the snails to trigger desperation eating, I gave then 2 days or so. I wasn't being super scientific, just curious.
All the eggs in with pond snails were eaten. One egg in with the ramshorns was, over maybe a dozen in 3 dishes. I may have misjudged its fertility.

My Cory breeder friends were more rigorous, and they repeated their experiment with Corydoras aeneus several times. They wanted something solid they could make a presentation to our club with, so they gathered more data.

Their result was different - the pond snails didn't eat the majority of the eggs. The ramshorns ate none, like with my killies, and they decided to only use ramshorns in their incubation trays. The fact most of their eggs survived the bladder snails may be due to the eggs. We look at them as objects, but they're alive. Some fish eggs have chemical defences against their predators, and maybe the Cory eggs had better chemicals than the killies. That's pure guessing.

Someone with the right laboratory tools and time on their hands could play with that one, and maybe learn a lot more. My conclusion is that bladders must burst. I squish them if they're small (the fish eat them) or introduce them to my turtle if I can pick them up. Ramshorns get to thrive, as they are also good indicators of overfeeding.

When my cories began spawning, I read somewhere (I think from Ian Fuller, but don't quote me on that in case I've forgotten and misattributed) that neocaridina shrimp are useful to have with cory eggs and fry - since they eat the fungus that often afflicts cory eggs, and can ruin more as it spreads, while they don't damage the healthy eggs at all. I began trying it, and did have more fry survive, but I didn't do a control group, or do it in any kind of scientific way. But I'd still add a few of my cherry shrimp to an cory egg container if I were saving eggs and trying to breed them again.

 

[Back in the fold]

What’s not to like about the humble and lowly Pond Snail ? I say Pond Snail and not bladder snail because it sounds more dignified . Get too many and you can pick them out . They are the best algae eating snail ever and I think they are the Canary in the coal mine for aquarists . If your Pond Snails are alive , healthy and reproducing then all is well .