JimWelsh
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1426
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- Joined: 1/22/2010
- Location: Angwin, CA, US
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Re:Breeding Journal, Species: Pseudochromis cyanotaenia
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Tuesday, April 16, 2013 2:11 AM
It has been over a week since I updated this journal. No word yet from Reed, but I do think I have some additional information that makes me think my failures have nothing at all to do with their products, or how they are being handled by me. Book lovers, I have a new tome for you coming:
There was another spawn last Monday, one week ago. That spawn hatched on Friday night. The whole hatch went into one BRT, filled with about 10 gallons of broodstock tank water. They were fed ample rotifers -- enough to give about 20/ml density in the BRT -- that had been grown were RGcomplete, and were nice and very dark green when sieved out of the rotifer culture. I tinted the BRT water very lightly this time with RotiGrow Omega, and all of the other parameters (air, light, temperature) were the same as the previous rotifer BRT. By the second day (Sunday), I already had massive die-off -- well over 50%. Similar to the previous die-off events, the survivors seemed to do fairly well, with relatively little die-off once the initial massacre is over.
Now, the BRT used for this new batch is the same BRT as the one used for the previous rotifer batch. There just weren't enough of the previous rotifer BRT larvae left to be concerned with, and I needed the tub for the new hatch, so I sacrificed the few remaining larvae for the cause.
Meanwhile, the larvae in the copepod BRT have certainly done better than the rotifer BRT larvae from the earlier hatch. I did still get a pretty big dieoff on the morning of Day 3 with them, though. I think in this case, one contributing factor was starvation -- they had eaten more or less all of the Parvocalanus I had fed them. Accordingly, I immediately started feeding them copious rotifers, too. I had virtually no more deaths in this BRT after that, until I started adding NHBBS (see below). Nonetheless, I do seem to be very consistently getting a very large dieoff somewhere between 36 and 60 hours post hatch, with very great consistency, with both my P. cyanotaenia and also the P. tapeinosoma hatches I've worked with. I'm starting to think there is something fundamentally flawed with my approach to larviculture that is the root cause of this.
Now, bear in mind that although I have a big pile of MBI points and a shiny medal and all that -- most of what I got those points for are things other than conventional "fish larvae raised with rotifers and BBS in a BRT" kind of things. Heck, my clownfish success stories have been entirely unremarkable in terms of survival rates. So the first thing I need to acknowledge and learn from is that I have very little experience and even less success at basic larviculture. In fact, so far, it is pretty easy to construct an argument that I pretty much suck at it.
I have spent a lot of the last week re-reading Moe's "Breeding the Orchid Dottyback" book, and in particular, Chapter 8, "The Great Run!". I have also done a lot of reading of the forum posts of others who have been successful at raising various species of dottybacks, both here on MBI and also on another moribund breeding forum. A few things stand out, for me (not in any particular order).
First, the basic idea that proper DHA enrichment of foods is essential at certain stages of larval development for dottybacks. Without it, failure is almost guaranteed. Second, Moe's emphasis on the importance of really good nutrition during the first day or so being very key for long-term survival of the larvae. Third, the importance of introducing small amounts of NHBBS and/or enriched BBS early -- certainly by day 8 -- and then weaning the larvae off of rotifers and onto the larger food gradually over the next few days. Fourth, Moe's usage of "wild plankton" at various stages, primarily as a source of DHA enrichment (I think), but also as a source of larger food items, too. Fifth, the degree to which larvae, even several day old larvae are susceptible to various forms of "shock", including but not limited to the "shock" from dripping water and/or food in from too great a height, or any other mechanical disturbance. Sixth, is the emphasis on antibiotics to control bacterial growth, especially once Artemia are introduced. Seventh, is the importance of regular water changes to keep water quality high.
Since I still have somewhere between 50 and 100 larvae from the copepod BRT batch described earlier in this journal, I have been working hard to apply the things I have learned to try to keep them alive. I have been doing roughly 15-25% water changes more or less daily for the last week (these should probably be larger still). When "dripping" in the WC water and/or more live Iso or diluted RotiGrow Omega, I have been submerging the drip line, placing it right below the airstone, to prevent any "drip, drip" shock, and to also maximize the degree to which the new water is being mixed with the old. I have been making sure that the water stays tinted with live Isochyrsis (high in DHA), while also adding something like about 10-15 drops per day of RotiGreen Omega, together with some ClorAm-X solution, at about a 2:1 ratio of CAX to RGO. I started adding NHBBS -- but VERY, VERY few -- on day 7, and have been enriching the BBS with Dan's Feed, hatching new BBS each day, and adding small but increasing amounts of both NHBBS and day-old enriched BBS, each day. I started adding Kanamycin at the same time as the Artemia, according to the instructions on the Kanamycin label. I did see the first deaths in several days right after adding the NHBBS. Today, at the end of Day 10, the remaining larvae (50 to maybe 100 of them, but more likely closer to 50) are larger and stronger than any I've ever seen at Day 10 before. I also added a bunch of Apocyclops and Parvocalanus this evening.
Early last year, when the P. tapeinosoma were first hatching for me, I had a private email exchange with both Matts (Pedersen and Wittenrich), and I have also re-read that email thread this last week. A few things stand out from Dr. Wittenrich's comments. First, he suggested that early dieoff may be due to transfer stress in the handling of the eggs/larvae during hatch, and made some suggestions to more gently treat the eggs and newly hatched larvae to avoid transfer stress. Upon reflection, I think that perhaps my hatch induction method may be causing excessive "transfer stress", and may very well be the cause of my consistent massive dieoffs in the 36-60 hour period, despite numerous other variables. He also suggested that I could be exhausting them with excessive air through an airstone, and made the recommendation to have only a single bubble in the water column at once through an open-ended airline. This is a recommendation that I have not yet followed.
I still have a lot to learn about more gently treating these delicate little souls entrusted to me! The parents have not yet spawned as of today, but have seemed "ready" for the last two days, so perhaps tomorrow is the next spawn day for them. I'm just hoping that they will continue to give me chances.
Meanwhile, I don't have a lot of hope for the most recent batch -- I think I've doomed the survivors of the first big dieoff with excessive caution and just too little enrichment of their rotifers with too little RotiGreen Omega -- they are just looking too thin and weak to me. I'm cooking up a big batch of Parvocalanus, and also Apocyclops and Acartia in preparation for the next batch, though, and, as usual, have a plentiful supply of live Isochrysis.
I'll also do everything I can to keep the momentum going with the 50-100 10 day olds I have right now, who are looking so good at the moment.
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