Caridina japonica - breeding Vol.2

Through building and maintaining beautiful nature aquaria people re-learn the intricate connections between forms of life, plants, fish, microorganism and humans. Riches and beauty come from harmony, from balance. Aquaria are great teachers of this truth. TAKASHI AMANO


The 20th day, collapse!

There are just a few zoeas floating. The majority died off in the last two days. I am not sure what was the problem this time.
I was looking forward to raising Amanos. I will probably try breeding Amanos next year again (will rest from them a bit). Instead I will try to breed less demanding species like Neocaridina denticulata sinensis-red and some other nicely colored Caridina/Neocaridina species, that desire no marine/brackish condition for rising the young.


14th day of full salinity

I changed 2 liters of water today and scarped the green phytoplankton off of the walls, so there is lots of food particles floating around. I will not feed for next 3-4 days, thanks to that.
It is hard to count, but there is approximately over 40 larvae floating around.
Some of the larvae are 18 days old.


7th day in marine water

Most larvae are alive and doing fine. Some of them still get caught in the surface.
I feed very little every second day, but rather stir the bottom with a spoon to lift all the settled phytoplankton food up, 3 times a day. I observed a few larvae holding on to a green piece of phytoplankton. It is impossible to make photos in this greenish water. I hope I will be able to make some good shots when the larvae transforms into the mysid stage.

Since the other two females didn't release their eggs (hatched) and started refusing food, I decided to return them back to the 180 liter main tank. I took them out of the main tank too soon. Two weeks sooner. many say that if the eggs have two eye like dots, the eggs are very close to hatching (in a few days). I don't think this is true, because my females eggs had those dots after carrying them for just two weeks. Scroll down the page to see the photo.


One female is ready :-)

Today one of my females released all the eggs. They hatched in the early morning hours. I returned that female back to the main 180 liter planted tank. She is behaving as normal.
After a few hours spent in freshwater hatching jar, the larvae are transferred to the marine water tank. I could count around approx 40 larvae, could be more.
So far I changed the water 3 times (20%). Water salinity is maintained at 1.025 SG (33.2).
I fed today a bit more with phytoplankton.
I had a problem with larvae getting stuck in the water surface. I read Noren's article again where he mentions this problem and increasing water flow (air flow through the air stone) should fix that problem. Now the water flow is a bit stronger.
Two females to go. I fed the females (in the hatchery jars) with very little algae Hikari food today and they are eating it.


The second batch added

Yesterday one of my Amanos released approx 20 more zoeas. I was waiting to see will more eggs hatch, but on my disappointment...nothing. I took 2 liters out of the salty tank (first water change) and poored in the water from the hatching jar together with the free floating zoeas. The spec. gravity went down to 1.023 (30.5 ppt). I poored enough of the prepared salty water from the 1.5 liter bottle to raise it back to 1.025 SG (33.2 ppt).
I didn't performed any water change by now because there was no need for it. I did not feed the larvae for the last 5 days because the water was still greenish from the food (sign that there is some food left in the water). All I did is occasionally stir the water with a spoon to raise the food fallen to the bottom (3 times a day). I fed a little amount of phytoplankton food today just to make sure everyone has enough of it.
Now there is approx. 40 zoeas floating.
Even though there is no surface film, some larvae get caught in the surface. Strange?
When that happens, I simply push them back into the water. I realised this was happening because of the air bubbles. The air stone was reduced but this time I reduced it even more, so there is only a few bubbles coming out of it now.
The water in the hatching jars is changed totally every 3-4 days. I don't want to put my females in danger from ammonia/nitrite poisoning. The water is conditioned with dechlorinator.
The more zoeas, the more food, the more water changes :-) is what I am going to do.
NOTE; the Amano females still carry lots of eggs.


4th day since the few zoea hatched

A few larvae hatched 4 days ago. I was hoping more will hatch, but nothing happened. I decided to transfer the larvae into the salty tank. The specific gravity is at 1.025 (33.2ppt).
I fed the first food for artemia. I will feed very little 2-3 times a day, since I have only about 20 zoea. The rest of the eggs should hatch in the next 10 days time.
I prepared a 2 liter bottle with salinity over 1.050 for the water changes, so I just have to add a little bit of already aged salty water to keep the 1.025 SG.


Eggs have eyes !

Today I did a macro photo to check on the eggs, and here it is! They have eyes ! I am not sure when the females started carrying the eggs but this indicates that the eggs might hatch in within the next 7 days, and for that reason I transferred the females to the hatchery. The shell is full of brownish dots, so one can't be sure are they eyes or not. The arrow is pointing at the few eggs that are at the end of the pleopods, not hidden under the shell, and they clearly have eyes (Click photo to enlarge).

I have one concern though. I am not sure are the hatchery jars stable to keep the ammonia/nitrite down at all times. I did wrap seeded filter floss around the air stone to jump start the cycle, but you can never be sure. Noren's and French article don't mention anything about preparing the hatchery, did they cycle it or what? Did they feed the female while in the hatching jar? I will feed mine a very small amount tomorrow, just to see will it eat, if not I will remove the food. Anyway, the carrying females are in there, and I hope for the best. I added one stem of Hygro polysperma into each jar. I am not sure will the Hygro grow because the light is not that strong. Will check on it in the next few days. It is a bit frustrating, have to say. I would hate seeing the females suffering in those small jars :-( It would be really great if at least one of them would hatch in next few days so I could return them back to the 180 liter again. All I need is one batch, for this experiment.

( EDIT; a few hours later) - I have noticed several zoeas floating in both hatching jars. Did it start already ???! There is a bit of a water current, which could be the reason for early hatching or did I miss the actual date when the eggs were developed in pleopods? Hm...
Photos by Dusko Bojic.


The hatchery is ready :-)

I built the hatchery inside the wardrobe (only space left for tanks). The small plastic container on the left is for water changes (preparing the salty water). Next to it are two glass jars (1.5 liters, with air-stones) for the carrying Amanos, where they will hatch. Those jars are cycling at the moment. I wrapped some of the used filter cotton form my established tank, around the air stones to jump-start the cycle. I don't want the Amano females suffering due high nitrites. Will add one stem of Hygrophila polysperma into each jar so the females have something to hold onto. Maximum 4 days after the hatching, larvae will be transferred into the marine water tank on the right (with the blue cover). Salt is already added, and the water is agitated by an air-stone. I would like to have aged water when time is near. Specific gravity is 1.027 (or 35.8 ppt, I used this converter). I will lower it down to 34 ppt before adding all the Amano zoea. One bulb is placed over the rearing tank (7W compact fluorescent) and will be on for 24/7.
The big white tank on the back left, is a freshwater tank with gravel substrate and is cycling at the moment (same, aged filter cotton around an air stone). After the cycle is finished I will add a few Malaysian Trumpet Snails to keep nitrifying bacteria happy until the young Caridina japonica shrimps "arrive" :-) Can't wait to meet them!!!
Photos by Dusko Bojic.


13th of August eggs !!!

3 of my Amanos are carrying eggs again. Why again you might ask? For a month or so my Amanos have been releasing their eggs after just 7-10 days. I thought that fertilising PMDD might have caused that problem. I used to fertilise every week. Will do it from now on every month. I disconnected the DIY CO2 Yeast reactors.
I hope my Amanos will feel better now :-)
I will do photos of the new breeding equipment that I bought the other day.
This time I am following the Mike Noren and the French article, so no mistakes any more.
Fingers crossed, and knock the wood 3 times for good luck :-)

To mention; I added some filter floss/cotton to my established filter (180liter) to seed nitrifying bacteria on it. I will wrap that peace around the air stones in both tanks, 2 liter hatching and the 15 liter raising tank. I hope that this bacteria will help keeping ammonia/nitrites low. I will add some activated carbon to the hatchery but not into the raising tank because it might reduce the tracing elements from the sea salt, that larvae need for normal growth. My plan is to put egg carrying Amanos into the 2 liters hatchery two weeks before the hatching, just to be sure.

Kind regards, Dusko.