Banggai cardinalfish (Pterapogon kauderni) Eating Eggs

I have a beautiful, fat, wild caught pair of Banggai cardinalfish (Pterapogon kauderni) I've raised from about 1.5" that spawn on the clock. My problem, as many of you have also probably have had, is that the male eats his eggs. Here's the culprit and the victims:
 

(such a tease)
This particular male I have usually starts gobbling at around day three or four. I feed them twice a day with LIPOVIT enriched frozen large freshwater mysis. So he seems fat enough. Here is my breeding journal datasheet: http://www.tcmas.org/foru...ostcount=1  
 
What are my options? Any feedback and/or suggestions are appreciated.

Live and Learn

I've had this behavior start after about 2.5 yrs of age. I haven't figured out if it's a problem with the eggs not being viable (female issue) or the male not being able to incubate (male issue).

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

Tal, didn't your pair still hold some to term? How old are they now and have they produced a hatch recently?

1. Does anyone out there have an old pair (3+ years) of kauderni still producing?
2. Does anyone know the average life span of these fish in the wild?

 

Live and Learn

I got my pair at MACNA 2008 and they were juveniles. He hasn't held to term since the first of the year. He holds for a few days now but  not very often.
 
Frank Marini did a study several years ago that showed this rise and fall in production.

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

 
I've seen that study but I'm in denial 
 
I would like others to chime in. Anyone else out there had this experience?

Live and Learn

Sorry man, you asked.

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

Yep, I have this issue with my older pair.  I actually have not had him hold to term yet, although he got close once.  I have two pairs and one has only had one failed batch, which is actually probably my fault because I went to bed isntead of waiting for release.
 
Background:
Successful pair: around 3 years old and were experienced when I got them carrying successfully, but with low count at release
Failing pair: around 5 years old, was told had mated, but fry were never raised and they had not carried in at least a year.
Both pairs get the same feeding regiment.
 
What I am finding (and testing right now, as both pairs are carrying), is my older pair seems too entised with food. During eating this pair tends to strike food much more aggressively than the other pair.  He usually swallows in less than a week, in, but the one time he almost carried to term (at 20 days roughly)...the fry were hatching/hatched in his mouth.  Then they were gone.  What I noticed during this event was he just could not resist eating....I know factually he was carrying, as I was just observing the fry moving in his mouth, and I fed the tank for the female, and he just could not resist the food.  That was it, he took a huge bite of the food.  I know I am anthropomorphising, but i swear he had a look like, o sh** after he took a huge bite.  Next batch, he failed to carry with in the normal time frame. 
 
They then took a pause for about 2 months, and now I have the ones he is holding now.  So this time around I removed him from the females tank after one day and he is in his own tank now where the fry will be raised.  We will see if food proves to be the issue.
 
I am sure that improper nutrition of the female could cause bad egg batchs that would be discarded too.
 
My assumptions is that diet is correct on my pairs, but stimulus (food) is what is causing him to fail.  He is only at day 5 now, but so far he is calm and all is good.


Caesra,
 
Thank you for the thoughtful insight. I too have been hypothesizing on food temptation and it's effects on the male's ability to hold eggs.  Because I too have see those big eyes when food comes around My intuition was to isolate my male at some point as well to investigate this further. I'm glad you've already started this effort and have decided to share your experience. One other observation I have in this regard is that if/when I miss a feeding in the morning the pair seem to spawn durning that window. There is nothing scientific about this observation but I've noticed this more than once.
 
Environmental stress is also a factor. Yesterday I did routine maintenance on my tank and he almost immediately consumed all if not most the eggs.
 
I'll be interested to see if these observations are shared in this book once it comes out:
 
The Banggai Cardinalfish: Natural History, Conservation, and Culture of Pterapogon kauderni
 

Live and Learn

After spawning I reduced my feedings as I was concerned about this issue. I had several successful spawns until while away for a weekend it appeared that the female killed the male while holding. I never saw any aggression between the two prior to the disappearance of the male but he was holding at the time and just vanished without any trace.
 
I would say it is worth a try to reduce feedings while the male is holding. If he can last a month the female can too and if you can seperate the pair during that period easily I say try it too.

Chad Penney - MBI Council
Agis quod Adis

Well this attempt at removing the older pair failed.  He held until today.  But my PJs and other pair of bangais all failed too.  So in my case I am thinking something else is up.

Can you all share pictures of what the tanks look like that these fish are kept in...I almost wonder if the environment has anything to do with it.

Chad Penney - MBI Council
Agis quod Adis

my tanks aren't as easy to take pics of, so Ill just be descriptive.  I keep my bangaiis tanks decorated because they seem to be more comfortable in there.  So 1" of crushed coral, live cheato and a few peices of decent LR.  They are in a 16g.  I have had several batches in this setup.
 
The two major changes that I have had for my one pair that normally is fine is the water temp is higher than it use to be (currently lowering it down a few degrees).  and my PJs went in next door (adjacent tank)...but they really don't seem to care about each other and I have had several batches of PJ held to term in this scenario too.
 
For me it might be a tank issue, but the scenario doesn't seem to support it, unless there is some sort of 'long term' effect on them, meaning the change to this setup didn't effect them for several batches, but that doesn't make alot of sense to me.
 
P.S.
 
I guess I do have one crappy pic of their holding tanks.
 

 

You bring up another factor that may be important as well. Thinking back all of my spawns have been much more successful when the water temps were cooler. My Banggai used to be in the basement and did great. I also had some nice spawns fom my pair in the display tank upstairs during the winter, which is when the tank temps are cooler. It wasn't until it started to warm up that I started running into problems.

Chad Penney - MBI Council
Agis quod Adis

When you say cool... how cool? 

Live and Learn

My system used to stay right around 76-78°F petty much all year round. Most of it was in the basement so it used to be that keeping the temp up was always the problem.

Chad Penney - MBI Council
Agis quod Adis

well my broodstock tanks holding my cards is slowly dropping to 78, so we will see in a few weeks what happens.

Here's the tank mine are in:

 
My male seems to eat the eggs whether its 76F or 82F :\

Live and Learn

There's alot of other fish in there...could that be causing him to get startled?

 
Defiantly could be. The fact that they spawn regularly seems as though they're not too bothered. However, he does get more skiddish when he's holding. It's just weird, though. He always eats on day three or four.

Live and Learn