Clarkii Larval Rearing (no rotifers?)

[Worldwithin]

It is hard to say if I would suggest putting them into your grow out tank. They will still be extremely small in size, and can easily get lost in the tank. Also, considering you need to keep the food density high enough for them to find, you may run into a nutrient issue in that tank. The Mag 350 will most likely suck them up if they get anywhere near the intake.

I totally undsertand waiting to harvest your continous culture... I would still harvest some of them, but not anything like 50%. This will still allow room for increased density, but also give you some extra food.

:fish1::hammer:

 

[jnowell]

OK, so I left the house at 7:00 and all was well, when I returned at 11:30, one of my microalgae cultures had completely crashed. It was mostly clear, and all the algae was clumped together at the bottom. I assume this was a bacterial infection? They were all started from the exact same water, 3 are fine, one is gone (all have filter floss covering the opening). I stirred it up to see if maybe it could be recovered, but I don't think so. The others look smooth, kinda like antifreeze, this one is very granular and a duller green.

At first I thought maybe it was a rotifer contamination, because there were tiny particles floating around in the clear water that resembled rots. Under a loupe, it just appears to be small chunks of algae still suspended in the water. The air was still running when I came in, I just shut it off to see if there might be rotifers in it. I'll check it again in the morning.

Here's a pic...any guesses?

 

[Worldwithin]

I ran across what causes that somewhere, but just cannot remember where I found it.... If I recall, I think it has crashed. If I manage to find it again, I will post it unless someone else beats me to it.

I don't think that rotifers are causing the problem.. If it was a rotifer infestation, they would just eat the algae and multiply until you got a rotifer colony instead of an algae colony.

Give this thread a shot to see if it is in there somewhere:
http://www.reefcentral.com/forums/showthread.php?s=&threadid=638436

I think I ran across something similar to that in there, or it was in a book somewhere... Regardless, I am sure that someone has an answer for that one.

:fish1::hammer:

 

[Kathy55g]

Looks bacterial to me.

Do you bleach or otherwise sterilize your water and bottles before you use them? This would prevent such crashes, and works great for me.
Kathy (I would like to change that screen name, but the powers that be haven't answered my email)

 

[jnowell]

Actually, I just rinsed the bottles out with tap water, and let them dry upside down....THEN I read about adding some bleach, rinsing and adding de-chlor. As I restart the cultures, I'll be sure to use bleach. This was but one of the many pitfalls of trying to hack this together at the last minute. I am learning a lot though, thanks in a large part to my new hero's on this board

On a good note, I had great rotifer density this morning, and finally feel like I got the rearing tank up to the correct density with my feed this morning. Lost another 4 fry last night, but so far, it's always been the little thin ones (except the tranfer damaged casualty, he was healthy). That's just about all of the smaller ones, so now I've past day 3 with about 35 apparently healthy babies.

Now on to day 8 where I can kill more of them with BBS, time to practice my decapsilating skills.

 

[seafarm]

Regardless of your current density it is important to harvest your rotifers daily. Rotifers will live for 10-12 days but only produce eggs for 2-3 days so if your population gets old, your culture stops reproducing. Then you have your larger, older rotifers eating all your food, but not making any eggs. This is why batch systems crash after 7-10 days - the population of young fecund females drops to almost nothing.

We produce roughly 500 million rotifers each day and recommend harvesting a minimum of 33% of your culture every day. This statistically wipes out your older females, leaving just the young ones.

Our culture system has been running continuously for over 2 years at a standard density of 2500 - 5000 per ml (peak was 10,000 / ml) and we harvest 50-80% of our culture every day.

It seems counter intuitive, but to get your densities up - you have to harvest.

 

[jnowell]

Thanks Randy, that makes a lot of sense. I had ordered the live culture from Florida Aqua Farms, they spent two days in shipping, and I stocked the rearing tank, and two cultures from the order. I tried NOT to harvest for the first few days to get the densities up, with no progress. It finally became nessecary to re-stock the rearing tank, so I harvested 50% of the two batch cultures, 2 days later I had booming (by my standards) populations in each. Now that the populations are up, I havest 30-50% of one each morning, and the other each evening. Since I began this regimen the densities are increasing exponentially. It all seems so clear now

Any comments from a seasoned veteran like yourself on feeding the rotifers? I've been alternating between Roto-Rich and fresh grown Nanno Cl. They seem to eat the microalgae faster than the mix, and the extreme nutrients in the mix worries me when used for a dense continous culture.

Once my 10 gallon continous culture matures (with harvesting now), I'm planning to pull some out into another container, and give them the mix for 3 hours before feeding them to the fry. Am I on the right track? Nice sites by the way, I bet you get some business from me before I get through this

Thanks again,

Jason

 

[jnowell]

Randy,

Disregard the last set of questions. 20 minutes reading your web site answered all my questions (go figure). And you already have the aforementioned order Who says internet marketing doesn't work, and you didn't even have to spam me

J

 

[seafarm]

Hi Jason,

I'm glad our website was helpful. If you want to see some cool pictures of rotifers @ 7,000 ml check out http://www.rotifer.com/icrs2/pictures.htm. These pictures are several years old and not our current system, but still interesting.

As a microalgae producer I'm clearly biased towards algal feeds instead of yeast based feeds. Yeast based feeds are less expensive but more prone to crashing because they stimulate faster bacteria growth, and they require a lot more cleaning. But that's a much bigger concern in commercial hatcheries than in home setups.

 

[Armando]

Randy,

How do I harvest the culture in a way that I catch the older females and leave the young ones? Would the use of a 53u sieve do the trick? (assuming younger females would be smaller than 53u?)

 

[seafarm]

Unfortunately that won't work - the difference in size is too small. We've been growing them for several years and the only method we've found is the frequent and heavy harvests that uses statistics:

Day 1 - 50% harvest
Day 2 - 50% of the rotifers are 1 day old. Harvest another 50%
Day 3 - 75% of the rotifers are 1-2 days old. Harvest another 50%
Day 4 - 87.5% of the rotifers are 1-3 days old

I'm not sure my numbers are statistically perfect, but you get the drift. If you can find a way to harvest just the older adults your name will become famous in the aquaculture world

 

[Kathy55g]

<a href=showthread.php?s=&postid=6315470#post6315470 target=_blank>Originally posted</a> by jnowell
Actually, I just rinsed the bottles out with tap water, and let them dry upside down....THEN I read about adding some bleach, rinsing and adding de-chlor. As I restart the cultures, I'll be sure to use bleach. This was but one of the many pitfalls of trying to hack this together at the last minute. I am learning a lot though...

If you bleach the bottles and the water together, you will save time and bleach and have bullet proof phyto.

Here's what I do:

Add 8 drops of bleach to a soda bottle 2/3 full of 20-25 ppt saltwater. cap, shake, and store overnight.

Next day dechlorinate with prime or whatever, add 14 drops of MicroAlgae Grow ( that would work out to 1 ml per gallon) and top off with the greenest culture you have of live phyto. Put on an airline (bleach that too) to the bottom of the bottle, and lights on 16 hours a day. I use a timer.

After about a week to 10 days, start new bottle(s) with similarly bleached and dechlorinated bottles, fertilized the same way, using the nanno from this first bottle.

If you get your saltwater into a collection of bottles and then add bleach, you can store them indefinately until you need them. Makes it simple and easy. You can grow as many bottles as you have lights to light them.

When I started doing this, my nanno grew and still grows 6 months later, very reliably. Good luck, and merry xmas.':bounce1:'
Kathy

 

[jnowell]

Thanks again Kathy! Your advice couldn't come at a better time, as I lost another microalgae culture while I was at work today. I had one remaining when I got home, but luckily I had prepared bottles of saltwater/bleach last night. I started new cultures, two from the one remaining bottle, and one from the previously matured culture that I had in the fridge (it's been in there for about 48 hours, I assume that will work?)

The rotifers are looking great thanks to all the help I got here. Even the fry are looking better this evening due to the increase in food they can now have. They all have that good dark color when viewed from above, no more skinny transparent ones. Still a long way to go, but I'm pleasantly suprised at my success so far. Day 5 has begun, and I have 35 of about 50 or so doing well.

If I get some to survive long enough, all of you who have helped can have the pick of the litter for free if you want them

Merry Christmas to you too Kathy, now where's Santa with my 500 gallon complete setup.

Jason

 

[jnowell]

They grow up so fast

I finally got an acurate count, for some reason they all stood still just long enough, 37 at this point. I hope they do OK switching to baby Brine Shrimp...we shall see.

 

[jwreffner]

<a href=showthread.php?s=&postid=6326644#post6326644 target=_blank>Originally posted</a> by jnowell
They grow up so fast

Don't all children?

 

[Kathy55g]

That's a great picture of some well fed larvae. How did you take it?

 

[jnowell]

Well, I turned on the 15w Power compact bulb (so my digital camera could focus). Then I just put the camera in Macro Focus mode, held it down about 3" above the water surface, and pushed the button. I'm thinking luck had a lot to do with it

My camera is a Nikon CoolPix 5600 (5.1 megapixel) so it's pretty high resolution. I cropped this little section out of the pic to get it down to a manageable size. The actual shot was of a larger surface area, but the guys were all grouped together and happened to be mostly in focus. The trick is to get the autofocus to pick out a fish, rather than a side of the tank or something. Autofocus looks for a straight line to focus on (sorry, I was a photography major in college) so you have to frame the shot where the only straight line is the side of a fish. Macro allows the camera to focus much closer, but you can't normally use the zoom when it's active.

In short, put it in Macro mode zoomed all the way out, with the camera very close to the subject. Always shoot at highest resolution, and give the camera plenty of light to focus with, (but only the straight lines in the frame that you WANT it to focus on) use the flash for the actual exposure. Then, on the computer, crop the original photo down to what you want in the picture and adjust the brightness and contrast to pull out the details.

Sounds easy right? I took 7 photos and this was the only good one. You can use any software package to crop and adjust the brightness/contrast. I use Adobe Photoshop (expensive), but Microsoft Photo Editor (free) or MS Imaging or Paint (come with windows) will do fine.

Hope that helped, inexpensive cameras will rarely do a good job of this, mine was only about $300 and I bought it a year ago.

Jason

 

[jwreffner]

Photoshop too expensive

I use Paint Shop Pro from Jasc Inc...Much cheaper

 

[jnowell]

I went home for lunch today, and noticed another clutch of eggs...the others just hatched Friday night of last week, 4 days ago! Who put Viagra in my tank?

I guess any question I had about whether they would spawn regularly has been answered. Ding Ding, Round 2!

 

[jnowell]

Quick question, this morning, I got up early and was doing all my "chores" on my rearing tank before work (company lunch, so no noon feeding today). I syphoned the bottom clean, added some new water (very slowly, like maybe a half a cup every ten minues or so to a half full 10 gallon (temp and salinity were the same for both). Then I added lots of rotifers, hopefully enough to get them through until 3-4 when they let us out of here today.

After doing all of this, several of the larvae were swimming in tiny circles, head down, like the had lost their air bladder or equilibrium or something. Most of the them just kinda snapped out of it, and started swimming normally, and eating. A few were still doing it when I left for work. Any guesses as to what caused this, and is it serious?

Jason