Tadpole night vision?

[bugdozer]

I have been trying to feed my tadpoles brine shrimp during the day, so they can see them to eat them. If I feed at night with the room light on, the brine shrimps wriggle up to the surface, while most of the tadpoles lie around on the bottom and ignore them. I have been putting a little light by the bottom of the tank side to draw the shrimps down.
But how well can the tadpoles see in relatively dark conditions? Do they need much light to find their prey or do they detect it by water movement or vibration etc?

 

[PatchworkClocks]

As far as I know, axolotls have somewhat poor eyesight. They can smell things in the water, and much like predatory fish, they can sense movements. So they don't necessarily need to see the food, they just need to be able to smell and sense it moving.

 

[auntiejude]

Axie larvae have terrible eyesight, no sense of smell and hunt by snapping at things that move - brineshrimp, turkey basters, plants....
And they will shy away from light, leave their tub/tank away from any bright light sources, and keep it fairly shallow - maybe 1" deep.
Just bung the brinshrimp in and leave them to it, they don't need help from us!

 

[bugdozer]

OK I have two people telling me the opposite - can they smell or can't they? And if their eyesight is as bad as Auntiejude says, how are they detecting things that move?
For what it's worth, mine are not shying away from bright light but going towards it as they have learned it is where the shrimps congregate. I'm also keeping them in water deeper than an inch in order to minimise any spiking of ammonia and help maintain water quality.
Can they feed in very dark conditions, or do they need at least a bit of light?

 

[PatchworkClocks]

Axie larvae have terrible eyesight, no sense of smell and hunt by snapping at things that move - brineshrimp, turkey basters, plants....
And they will shy away from light, leave their tub/tank away from any bright light sources, and keep it fairly shallow - maybe 1" deep.
Just bung the brinshrimp in and leave them to it, they don't need help from us!

Oh, they can't smell when they're tadpoles? I thought it was the only thing they were really good at. Woops.

 

[Azhael]

Yes, they can smell, but small larvae tend to be much more visual. They see poorly in the dark but they can detect movement trough their lateral line so if food passes in fron of them, they´ll snap at it. However, they feed best when they can see the food and chase it. Larger larvae can get used to hunting by smell and may even accept pellets.

 

[auntiejude]

From axolotl.org: Within 24-72 hours after hatching, they will require food. From this point until they reach approximately 20 mm in length (a little under an inch), their diet must consist solely of live food items of a very small size. They will ignore dead food until they have grown significantly. This is because, instinctively, young larvae respond to prey movement alone. It is not until later that smell will play an important role in feeding.

My experience is that larvae retreat from bright lights - the same as adults - as mine swim away from the light I use to check on them. They are fine with ambient daylight or light bulbs. If other people's larvae are attracted to light because they associate it with food then great - it's just another experience to add to the axie world.

 

[bugdozer]

I began to wonder because of the frequency with which I see a tadpole sitting on the bottom with about five brine shrimps dancing about in front of its mouth - and it just ignores them. I'm trying to work out the optimum amount to feed them because if I put in too many they feed too slowly and I get dead ones left. If I don't put in enough, then they'll starve. However, they don't exactly help themselves by ignoring shrimp right in front of them. Which made me wonder if they even realised they were there..

 

[auntiejude]

Just bung some in, then change the water and clean the tub after about 4 hours - get rid of the dead brineshrimp. Their full tummies are bright orange so you can see if they have eaten.

Why do axies ignore brineshrimp right in front of them? Well why do you eat one mouthfull at a time when you have a platefull in front of you.....?

 

[wandering]

I am currently having a go at raising some from eggs. I am using microworm at the same time as brineshrimp mainly because the brine shrimp hatch has been patchy. I have the tadpoles in a small tank so when I lower the water and put in the food I can look from the side. The tadpoles are all sitting on the tank bottom and pop like popcorn as they snap at the moving food. Only yesterday at ten days old, have I seen them move away from the bottom.

Sent from my Nexus 7 using Tapatalk

 

[bugdozer]

Why do axies ignore brineshrimp right in front of them? Well why do you eat one mouthfull at a time when you have a platefull in front of you.....?

Because I have to. I can only eat one mouthful at a time and as soon as I've swallowed one, I have another. Pretty much all wild creatures, especially the young, will eat at the fastest possible rate they can. Because if they don't, that food source might be gone.