Full Fish Ahead: Part 5

Spring is the season for babies and Avalus has lots of new little cuties in his tank. Let’s go see.

Part 5 – Babies


Hey There! ©Avalus, all rights reserved

Not much going on in the new tank. I cut some of the faster growing plants, next week the platies will go back to the main tank and there will come new fishes (neon tetras (Paracheirodon innesi) and mosquito rasboras (Boraras brigittae)). Both are tiny colourful fishes, the neons are blue with a bit of red and the rasboras purple with a copper or golden tint.

But on to the titular babies. We already saw baby snails and the tiny platies and they are all growing well. This time we first take a look at the shrimp tank. In it there are shrimp, obviously, and some selected endler guppies. My population goes back to the school aquarium, the responsible teacher gifted me the fishes in 2005 when the tank was discontinued. The fish originated from an Institute in Cologne, if I recall correctly. What’s so special about these? Usually the females are of a green colour but last winter I found pair that are of a steely blue colour, so I separated them in the shrimp tank and caught all the fry with a blue tint. I also have a blue coloured male, so in the coming months I will try and see if the blue colour is inherited.* Yay, Biology!

In the picture below you can see them bickering with the various invertebrates over food.

Shrimps, guppies and snails bickering over nibbling rights to a food tablet. Many more young shrimps now dare to leave the thickets of moss, you can differentiate them from the adults via their red stripes. ©Avalus, all rights reserved

Now that green shrimp in the centre right is suspicious, is it not?

Yes, it’s a mommy! The green bobbles are the eggs .©Avalus, all rights reserved

These freshwater shrimp keep their eggs attached to their fins until the young hatch and the hatchlings will be complete shrimps. This is unusual as any arthropods go through nauplius and/or zoea states before they reach maturity. It also means, that these shrimps (mostly neocaridinae and some caridinae species) multiply their numbers quickly. On the flip side, they don’t get very old, usually 9-18 months. Compared to that, the amano shrimps get really old, some of mine are over 8 years old now!

A bee shrimp, Caridina cantonensis. They also “give birth” to fully developed shrimps. This colour variant is called crystal red. And this individual is about 1 cm long. ©Avalus, all rights reserved

Remember her?

©Avalus, all rights reserved

Now in the meantime at least two more amano shrimps developed eggs.

You can just make out the eyespots of the developing larva in the eggs. Hatching is close! ©Avalus, all rights reserved

The offspring of these amano shrimp (Caridina multidentata) are not ready shrimps but zoea larva. These need to reach saltwater within a few days and then feed on phytoplankton or die. In nature this transportation service is provided by the rivers these shrimp live in. However, it makes breeding them in captivity difficult. I had read a lot on this topic in the past and wanted to try it out, but did not get around to do it. After discovering the additional pregnant females I talked with the people of my zoo shop and they were both very excited as well and decided to help me along. So I called a friend who owns a car and went home with two small aquaria (both 12 L) and a generous amount of salt for marine aquaria, all of it gifted. Thanks T. and A.! I also went against my standards and bought via the internet several litres of a solution of the marine algae nannochloropsis salina along with some special fertilizer.

At home I placed both tanks on my windowsill, put some sand from my main tank, some Ramshorn snails and some moss in one of them, waited a few days and then caught all the egg carrying amanos I could find, which was four. When the algae arrived I prepared a seawater solution and filled the second tank with a beautifully vibrant green liquid.**

Some privacy please, I am trying to spawn here! ©Avalus, all rights reserved

And actually not a day too soon, because this morning (21. April) I saw several tiny, nearly transparent things jumping through the water.

They’re so small, transparent and always moving, near impossible to photograph for me. This is a composite image, in the insert (to scale) you can see the eyes of a zoea. ©Avalus, all rights reserved

Luckily I had also gotten a hold of an old microscope*** so I caught one larva with a pipette and had a look. Photographing with my cell phone through the eye piece was surprisingly easy.

©Avalus, all rights reserved

©Avalus, all rights reserved

©Avalus, all rights reserved

This magnificent beast is about 1 mm long and only visible in the aquarium when it moves or if it sits in front of a dark background. With the naked eye you can just make out the black eyes. The zoea is constantly treading water and I had to adjust the plate constantly so I am rather proud of these photos. It is now in the greenwater tank and will be joined by its brothers and sisters this evening.
Now a few hours later the ground is littered with hatching shrimp eggs and the water is filled with jiggling transparent commas. The larvae are attracted by light so I will siphon them out when it is dark outside.

Suddenly grains of sand become huge boulders! (the eggs are next to the green loop) ©Avalus, all rights reserved

I am too excited for a rant, see you next time!



*Blue endlers’ guppies are not new but I have never seen them in shops. My vendor was definitely interested in me maybe breeding them.

** I also cultivate the freshwater algae Chlorella vulgaris for my daphnia so I have some experience there. Just having glasses of green liquid on my window bench is actually rather pretty.

***Thanks to N, a friend of mine who studied biology and had it in his cellar. I can’t say what magnification it has. He said that it is scavenged from different parts and the printed on values are not correct. I could not get any images of the saltwater algae, as the higher magnifying lenses are pretty dirty. But hey, it was free!


Link to Full Fish Ahead: Part 4




  1. Jazzlet says

    Good luck baby shrimp!

    The blue endler guppies are rather cute, good luck to them breeding true too.

  2. rq says

    I’m so excited for the baby shrimp! Who are not yet real shrimp! They’re real cuties and I hope your experiment is successful!

  3. avalus says

    Thanks all, a second amano shrimp just gave birth, this time I got some nice photos of the larva in free water.
    The older larva have already grown to 3-4 mm!

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