pleopods and swimmerets are the same thing. The small things they have under the tail that are fanning. They have 10-20 sets (depending on species) under the tail that are used to help the shrimp swim, and for females to carry eggs on.
In addition to the pleopods, shrimp and crabs have 5 prs of legs. The first pr (closest to the front of the shrimp) are normally modified into claws/ pincers, and the other 4 sets are used to walk around on.
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When you say the shop gave you a bag of dirty water, was it just water out of the tank or was it stuff they sucked out of the gravel? Because you don't want crap out of the gravel. Gravel from an established aquarium has good and bad bacteria on it. The bad bacteria comes from the gunk/ sediment in the gravel and that is primarily fish poop.
The best way to transfer filter bacteria from an established tank is either filter materials like sponges, or gravel that has had the gunk sucked out. Then the sponge or gravel (from the established tank) is put in contact with gravel or sponges in the new tank, and the bacteria can quickly spread across the new filter media.
If you have an undergravel filter, then put the bag of gravel from the shop, on the gravel in your tank. Then the bacteria on the shop's gravel can spread onto your gravel. You don't have to spread the shop gravel over yours. Just leave the shop gravel in its bag and rest that bag on your substrate.
If you had a power filter, then you put the bag of shop gravel in the power filter on a sponge so the bacteria can spread to the sponge.
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For optimum survival of any shrimp larvae, you want to reduce predators in the environment (no fish or other species of shrimp in the tank), and lots of food for the adults, and lots of plants for the young to hide in. However, this defeats the purpose of a community aquarium. Your best bet in a community tank is to have lots of plants for the adults and young to hide among. And feed the fish well. Having said that, you need to keep the feeding down until the tank is established. Until then you will have to let nature take its course and if anything survives, that is great, but you might not get anything.
The shrimp eggs hatch during the day or night but the larvae are not released until after dark. This allows the larvae a chance to swim off into the wild blue yonder and there is less chance of predators (mainly fish) eating them.
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Is the yellow shrimp the same species as the red one?
Has the red one been with any others of her kind during the last month (when she moulted)?
Basically shrimp breed immediately after they moult (shed their old skin). This is the only time the males can impregnate the females, while the females shell is soft. If you have only had the one red shrimp for a month or so then it might not have eggs and is simply cleaning herself. However you mentioned she moulted about 3.5 - 4 weeks ago so if there was a male with her at the time, then she probably bred with him.
In most species, male shrimp are normally smaller than females, and females have longer pleopods and the sides of their tail usually come down further to help cover up and protect any eggs they are carrying. Altho these differences are pretty small and hard to see. Other species of shrimp are hermaphrodites and act as receptive females when they moult, and act as males when others moult.
In addition to the pleopods, shrimp and crabs have 5 prs of legs. The first pr (closest to the front of the shrimp) are normally modified into claws/ pincers, and the other 4 sets are used to walk around on.
------------------------
When you say the shop gave you a bag of dirty water, was it just water out of the tank or was it stuff they sucked out of the gravel? Because you don't want crap out of the gravel. Gravel from an established aquarium has good and bad bacteria on it. The bad bacteria comes from the gunk/ sediment in the gravel and that is primarily fish poop.
The best way to transfer filter bacteria from an established tank is either filter materials like sponges, or gravel that has had the gunk sucked out. Then the sponge or gravel (from the established tank) is put in contact with gravel or sponges in the new tank, and the bacteria can quickly spread across the new filter media.
If you have an undergravel filter, then put the bag of gravel from the shop, on the gravel in your tank. Then the bacteria on the shop's gravel can spread onto your gravel. You don't have to spread the shop gravel over yours. Just leave the shop gravel in its bag and rest that bag on your substrate.
If you had a power filter, then you put the bag of shop gravel in the power filter on a sponge so the bacteria can spread to the sponge.
------------------------
For optimum survival of any shrimp larvae, you want to reduce predators in the environment (no fish or other species of shrimp in the tank), and lots of food for the adults, and lots of plants for the young to hide in. However, this defeats the purpose of a community aquarium. Your best bet in a community tank is to have lots of plants for the adults and young to hide among. And feed the fish well. Having said that, you need to keep the feeding down until the tank is established. Until then you will have to let nature take its course and if anything survives, that is great, but you might not get anything.
The shrimp eggs hatch during the day or night but the larvae are not released until after dark. This allows the larvae a chance to swim off into the wild blue yonder and there is less chance of predators (mainly fish) eating them.
------------------------
Is the yellow shrimp the same species as the red one?
Has the red one been with any others of her kind during the last month (when she moulted)?
Basically shrimp breed immediately after they moult (shed their old skin). This is the only time the males can impregnate the females, while the females shell is soft. If you have only had the one red shrimp for a month or so then it might not have eggs and is simply cleaning herself. However you mentioned she moulted about 3.5 - 4 weeks ago so if there was a male with her at the time, then she probably bred with him.
In most species, male shrimp are normally smaller than females, and females have longer pleopods and the sides of their tail usually come down further to help cover up and protect any eggs they are carrying. Altho these differences are pretty small and hard to see. Other species of shrimp are hermaphrodites and act as receptive females when they moult, and act as males when others moult.