fry mysteriously dying...

If it isn't to late, and you're desperately looking for some advice, hopefully someone can help you out.

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McEve
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Post by McEve »

so, now it's my turn. I just lost 20 2-2.5cm fry. Admittedly I haven't been able to keep up with the maintance as I should, (changed 50% every two weeks) The two adults, and all the fry that was 3-4cm was fine, fat and active and no problem at all.

I wonder if if the 2-2.5cm stage is a particular critical age where conditions really need to be optimal? Or did it just get too crowded for them and the smallest succumbed...

I had 37 fry in a 120L, feeding 4 sinking tablets day (Automatic feeder).
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KenW
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Post by KenW »

I am very sorry to hear about all the zebra losts. I too would like to add that I have lost fry ever so often, usually around 1 or 2 a week or less. I've had fry between .75 inches up to 1.25 inches succumb to this problem. I'm thinking and leaning more towards the bacteria and bio film idea.

My tanks use dechlorinated aged water that is matched with the tank water. I change their water 30 to 40% weekly and have tried 30 to 40% twice a week with no significant change. Whether it is a mineral deficiency or not I do not know. My losses are not as great but they are there. The reason I think that it is a biofilm/bacteria issue is that from talking to Barbie she cleans and wipes down her tank regular which probably eliminates or prevents the build-up of the biofilm/bacteria and she doesn't lose her fry this way. Also she has minimal decorations so there are less area for the bacteria to accumulate under things. She will have to clarify or correct me if I got that incorrect. One thing I have noticed is that everytime I setup a new tank for the babies they usually do very well, but after maybe 6 to 9 months to a year then I notice a few deaths here and there. I initially brought up an issue with some of my fry losing their tails in August and I wonder whether it is related problem. Several things I'm trying now is adding a thin layer of sand and cories to constantly stir up the sand to prevent build-up. I'm also thinking of adding some small bushy noses to the tank as an experiment to see if there algae eating activities would help prevent or eliminate the biofilm and bacteria build-up. One thing I would like to add is I keep small round snails in all my baby tanks to consume any leftovers. Maybe that could be part of the reason why I see fewer deaths. These are just some of my thoughts. I'm still puzzle by this and continue to read and experiment to get to the source of the problem.

Ken
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Post by crazie.eddie »

PM, I'm assuming you have your Vectron UV8 connected to the Eheim 2224. UV's usually have a specified dwell time (amount of time the water makes contact with the UV light) depending on the purpose. For example,

Accordng to Coralife's website, the instructions (page 5) state the following...
9 watt - 55 GPH to eliminate parasites, 121 GPH to eliminate algae, 253 to eliminate bacteria

18 watt - 110 GPH to eliminate parasites, 240 GPH to eliminate algae, 500 to eliminate bacteria

36 watt - 290 GPH to eliminate parasites, 680 GPH to eliminate algae, 1550 to eliminate bacteria
I'm not familiar with the Vectron, so I would have to assume something similar. The Eheim 2224 is estimated to produce about 185 GPH. Therefore, your Vectron would only be efficient enough to eliminate algae and bacteria, but not any parasites.
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Post by Barbie »

I'm not sure just how much light I can shed on this subject. The biofilm thing was news to me, per Ian's talk on cories. I do keep all of my zebras currently in bare bottom tanks. I do scrub the bottoms of the tanks along with the walls when I do maintenance on them, although probably only really thoroughly once or twice a month. The decor in the tanks is a few flat rocks to get under, a piece or two of bog wood, and caves, basically. I also have ancistrus in with one group of zebras, which would also keep the biofilm reduced, if that was actually a problem.

I recently lost 7 snub nosed zebra fry I was growing out to work with, along with 2 perfect babies that were almost a year old that I was talking myself into keeping. I had fish shipped in for a friend and when one came in sick, I needed a warm tank to float the container in that I had to stick him in. It was definitely a virulent buggie. I lost any fry under a year old, ancistrus, L260, and zebra alike. That will teach me to try to do a favor, I know ;).

I don't usually have large scale losses of fry, but then again, until recently, my spawns hadn't exactly been regular either ;). No bloodworms, no large foods they can choke on and scrubbing the tank down was working for me, but I also use 40 breeder sized tanks for the bulk of my fish, as well as do weekly 40% water changes in understocked tanks. I wish I was more help. Maybe my "fishues" with cleaning stuff have paid off, but I just couldn't say for sure.

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Post by Plastic Mac »

Hi CE,

Indeed my vecton 8 is connected to my 2224 and I am aware of the dwell time. Most as far as I am aware, if not all, pump statistics are the best possible flow rates without filter media and the out-pipe height taken into consideration. ie they just run the pump with no media and not having to pump it to any height and just measure it's best potential flowrate. Once you add media etc and, in my case put the outlet pipe about a meter above the filter then the flow rate reduces dramatically.

According to a quick bit of reasearch I did today the best rate I could get under current conditions is about 110gph...and i doubt it's even that good since I'm not taking into account the bends in the pipe, dirty media etc etc..

As for the vecton 8. It states on their site:

8 watt UV suitable for tanks of up to 50 UK/60 US gallons (230 litres) with a maximum flow rate of 150 UK/180 US gallons

So even at my best guessed flow rate I'm still well under the limit. Thanks for the thought anyway, it's another one to cross off the list.


To be honest...I kinda stopped replying in this thread as some members were coming to the assumption that it was a water/ r/o issue. I can't say exactly what it is but I do know what it isn't and it isn't water related at all. I still firmly believe it's a biofilm issue as Adam originally mentioned. The many water changes I performed to alleviate the problem had no effect, only once I scrubbed all the decor and cleaned the bottom of the tank did the deaths stop.

@McEve

I'm really sorry to hear about your losses. I don't know whether the 2-2.5cm size is critcal or not as my losses weren't just limited to a single size but instead seemed to affect fish from different spawns at different sizes. As I said at the time though it did seem to be related to one particular area of the tank....was this also experienced by yourself?
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Post by Jojoyojimbi »

did you have hydras?

i know if i get hydras in a cory fry tank, bad stuff starts to happen as the little guys get stung and stressed out, perhaps you had a type of hydra in the biofilm that was stressing the fry?
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Post by eklikewhoa »

ken, i would go with otocinclus instead of the bristlenose just in case there is a aggression issue between the bn and zebras plus the o-cats eat beard algae and stuff other algae eaters would touch and they are smaller so their bio-load would be less.

with the snails i have malaysian trumpet snails and they do a great job of eating what the little zebras dont finish and they dig through the sand to aerate it as well. mts are not bad snails that eat eggs and such either that i know of so it wouldnt be a problem to the fish.

i think that the nutrients in the water does have something to do with the babies health since their fry/juvi stage is when they need the most nutrients like any living thing. but this probably isnt the main reason for a lost.



im sorry to hear everyone's loss of babies.
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McEve
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Post by McEve »

Plastic Mac wrote: @McEve

I'm really sorry to hear about your losses. I don't know whether the 2-2.5cm size is critcal or not as my losses weren't just limited to a single size but instead seemed to affect fish from different spawns at different sizes. As I said at the time though it did seem to be related to one particular area of the tank....was this also experienced by yourself?
Sorry I missed this one! the mass death I had did include three different batches about a month in age apart from eachother. it wasn't limited to one space in the tank, but I know what you mean as I did loose three fry once all sitting on top of black sand. Obiously the sand had gone bad and they suffocated sitting on top of this area. You'd think they'd move when the noticed that it was becoming hard to breath, but no...

Why this is happening remains a mystery, but I do know it's happened to several more breeders, also here in Norway, all apparently without an obious cause...

I don't keep sand in my tanks anymore btw :roll: and yes, i did keep mts in the sand...

no problems with the survivors of the incident either, which happend in a tank without sand.
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Post by Andrew C »

Something to consider about the different aged zebra fry deaths, is the fry are basically off wild caught fish, or at most, probably first generation fish, and will not have as good an immune system as most fish that have been tank bred over the years and and are much more used to background bacteria in our water.
The different aged deaths could be along the lines of the hardier fry surviving and the weaker ones not, much like when you have a disease in your tank, where some fish survive but others don't, and i am not talking about a disease that wipes out the tank.

The more zebra fry that survive and breed, the better it will be in the long run, as fry from f2, f3, f4, parents, will have an immune stystem better adapted to background bacteria in our tanks, as is the case with most general fish on sale at lfs, where if you actually bought some wild caught fish and tried breeding them, you would find there fry a lot more sensitive to our tank water than their common tank bred counter parts.

Using a UV Sterilizer, scrubbing your tank every water change, making sure the water parameters & temperature are right before water changes, will help but you may always have some fry losses until you get tank bred fry further away from wild caught fish.

It is just something to consider.
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Post by Shimmy »

Hi All,

I know it has been a while since I last posted but I have had other priorities to sort (1 Year Old Son!!!).

We ll after what can only be described as a disasterous year in 2006 keeping from alive I thought I would pass on a few things I have now found out.

Firstly my first loss about the same time as plastic mac I have since discovered that there were several inbalances in the water we were getting from Severn trent (at the time I was using 80% R/O and 20% treated tap water.)

Then went onto using R/0 and adding R/0 rite this settled everything down and it wasnt until my helpful son added an alien body to the tank sending the PH from 6.1 to 7.4 in less than six hours!!

Since Sept I moved the remaining dozen fry back in with the adults and everything was going great until today. Out of the blue lost one 8 month old fry and one of my 5 week old fry that was in a breeding trap suspended in the main tank.

I must admit reading through all of the inputs from the experienced breeders makes me think that losses are inevitable.

IMO and please take it with a pinch of salt as I am hanging on to it to try and keep my sanity. IS that some deaths will be down to food ( I have found peices of foreign bodies in my food that I know are plastic.) Some will be down to bacterial build ups and the rest will just be down to the genes, there is no such species that has a 90-100% success rate and although some illnesses tkae effect immediately others take time before they take effect.

I think as long as we are not seeing mass deaths over a few day period then I think that if we are all doing the regular good house keeping then we should see a trend between fry spawning numbers and fish survival at the end of twelve months?

I would be interested to hear how everyone else is gettingon with this in the next few months. See if we can see some form of pattern!
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Post by Andrew C »

Plastic Mac
How are you getting on with the mystery deaths, do you have any idea what may be causing it ?

I lost my first batch of six fry over two weeks in a hatcher in the parents tank, while the male was hatching out his second batch.

Moved the second batch after they emerged from the males cave straight into the 2.5ft * 1.5ft grow out tank, with a thin layer of sand, one cave, an Eheim 2224 external cannister, and a Fluval 2 internal with some polyfilter in it, the tank gets a 50% daily water change with water the same temperature (29 degrees).
The second batch are about 5 weeks old now and i have lost three fry so far from the second batch, not all at once but over the five weeks, including one i just found today.

I have ordered a UV Sterilizer and am waiting for it to arrive to put it on the zebra grow out tank.
I feed them; Tetra Tabimin in the morning (grey tablets which dissolve, i break half a tablet up for them), some freshly hatched baby brine shrimp in the evening, and some Tetra Prima before lights outs (Red Granules).

Hopefully the UV Sterilzer will help, it should arrive tomorrow, and the male is sitting on another batch of eggs, with the fry due to emerge this weekend.
Luckily any fry that emerge so far are fully devolped (the male usually has them for three weeks in the cave).
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Post by Plastic Mac »

Hi Andrew,

I had one more brief spell about 3 months later, I lost 3 in 3 days and I then removed all the rockwork and cleaned it which appeared to be the solution to the original spate of deaths. Once again the deaths immediately stopped. So I'm now positive that Adams theory of it being a biofilm issue is the correct one. I now remove all the rockwork every couple of months for cleaning.
Although your first batch wasn't succesful, it sounds like things are improving at least on the second. Your mortality rates certainly aren't at the ratios I was experiencing over that first week or even the second time it happened so things do appear to be getting better. How many are left from the second spawn?

Good luck with the third btw.

Plastic Mac
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Post by Andrew C »

Hello Mac
Got seven fry left from the second spawn of ten fry, lost all the first spawn of six fry over a five week period, so the second spawn is fairing better.

The UV Sterilizer arrived on Tuesday and i fitted it that night, which luckily has worked out for the third spawn, as i found five fry just emerged from the males cave yesterday, and he is still deep in his cave.
Transfered the fry straight into the grow out tank, hopefully the UV Sterilizer will make a difference.

I have been reading over a lot of old posts about fry deaths and did not really find a good answer to it, one person said he found feeding microworms in the beginning stopped his mystery deaths, whereas, most answers points to the bio film.
Was told by another fishkeeper, discus keepers also had a lot of mystery fry deaths in the beginning, when discus were first imported (years ago).
Discus also come from rivers with a low ph, which makes the water pretty sterile, and wild adults that adapted and were eventually breed, had a lot of fry deaths.
He recommended a UV Sterilizer, not to stock the tank too heavily with fry and scrubbing the tank regularly, so, only time will tell with this new spawn i have just got.

I was not too kean on using a UV Sterilizer in the beginning, as i thought a fry's immunity system would be underdevolped, but now i think fry need to grow and mature a bit, before moving them into a tank without a sterilzer.

What are you feeding your fry ?
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