Fish hatching event in my 720 gallon tank - What could they be? Has this happened in your tank?

[AlexG]

Last night I gave the tanks a once over after lights out with a red flashlight to see if any interesting critters were out an about. The reef tank was pretty typical with everything crawling and the corals in night mode. I decided to give my 720 gallon tank which is more or less for larger non safe reef fish a once over. My porcupine puffer is normally out and about at night and some other fish now and then. I saw the water seemed to have lots of large particles all over the place which is unusual after lights out especially when the reef tank was crystal clear. I turned on the white light away from the puffer of course and the tank must have hundreds if not thousands of small critters around 2-3mm. I could see eyes reflecting back at me and they were making movements on their own. Since I had no idea what they were I grabbed a couple of small containers and scooped some water up. I got two of these little critters on the first try. I got them into a petri dish and under my stereo microscope. First look and I said those are fish! I was shocked so I attached my cell phone adapter to the microscope to take some pictures and video. I did not get any footage of the tank full of fry as they dissipated by the time I finished up with the microscope. Now the big question what are they? Has anyone else experienced a hatch like this before in their tank?

What are they?
I have mostly large fish in my 720 gallon that are not in pairs or are not mature adults (Tangs, Angels, Wrasses, Triggers, Puffers). I only have a few smaller fish which are exceptions. I ruled out these fry coming from the 480 gallon reef tank since there were none of these fry present along with the fact that they would need to make it though the sump/filtration system in one piece which is possible but unlikely due to the numbers I was seeing.

• 1x Flame Hawk (Neocirrhites armatus) - Not likely since there is only one of them
• 2x Orange tail damsels (Chrysiptera cyanea) - Maybe?
• 3x Purple Pseudochromis (Pseudochromis porphyreus) - Maybe?

I am leaning towards these fry being Purple Pseudochromis but this is just a guess based on the shape of the fry. I know we have a lot of folks in the community that might be able to help with identification. I released these little guys into my frag tank after they were under the microscope but I don't expect to see any survive in my system to adulthood.

 

[NanoDJS]

Super cool !

 

[HawaiianReef]

Now that is cool!

 

[El_Guapo13]

 

[secret_reefer337]

Very cool!

 

[MegaZombi]

My guess would be the chromis. My bluegreen chromis breed in my 180. Look for eggs on a vertical surface. Mine lay them on the side of the glass.

 

[Reef AquaCult]

Great video I would say pseudochromis based on your livestock. Would you mind sharing what equipment you used to capture it? Im looking into breeding pygmy angels and want to have some sort of microscope/macro videography. Thank you!

 

[Scdell]

I would lean towards the damsels spawning. I have two that spawn often.

 

[AlexG]

Great video I would say pseudochromis based on your livestock. Would you mind sharing what equipment you used to capture it? Im looking into breeding pygmy angels and want to have some sort of microscope/macro videography. Thank you!

Since I do mostly light duty work with the microscope I went the AM scope route. Having the ability to take pictures and videos with a cell phone is nice but it does hinder your perspective compared to a trinocular microscope with a dedicated camera port. The adapter is easy to clamp on and it just takes a little adjusting of the phone to get the view right. I have been happy with this microscope and have not experienced eye strain on sessions that last up to 20-30 minutes.

AmScope Cordless LED Stereo Microscope 20x-40x-80x Model: SE306R-PZ-LED, some petri dishes, and a Gosky Universal Cell Phone Adapter Mount.

Old picture from one my articles showing my microscope setup

 

[Katrina71]

I'd vote damsel too.

 

[ca1ore]

Hard to say. Veeeery cool though - how did you spot them? My clowns spawn all the time and I never see the fry.

 

[AlexG]

I wanted to give an update. I checked the aquarium again last night right after lights out and there was another hatch event. Not the best of videos but it did not last very long.

 

[AlexG]

Hard to say. Veeeery cool though - how did you spot them? My clowns spawn all the time and I never see the fry.

@ca1ore It was just random luck. I happened to look at the tank at the right time. I posted a video above of a second night of hatching on a hunch. I tried observing last night which would have been a third night and had the big camera ready but there was not any hatching activity. The video I posted above was just after lights out.

I am confident these fry are Purple Pseudochromis (Pseudochromis porphyreus). The damsels could not fit into that hole in the rocks. There is also a Purple Pseudochromis that frequently visits this little cave. Now I need to determine what their spawning cycle is so I can try and film this hatching event the next time it occurs. @chad vossen do you have any knowledge on the spawning cycles of Pseudochromis porphyreus?

 

[reef lover]

Thats awesome!!

 

[Peace River]

Wow!!! Thanks for sharing! Do you have a link to your microscope article?

 

[AlexG]

Wow!!! Thanks for sharing! Do you have a link to your microscope article?

The articles I wrote are on bioluminescence but I did utilize my microscope for much of the research for the article linked below.

https://www.reef2reef.com/threads/r...bioluminescence-observations-research.467493/

 

[ScottR]

Very cool. For such a large tank, you seem to have very few fish. But now you may have hundreds. Have you tried feeding them? Perhaps they’ll take rotifers.

 

[AlexG]

Very cool. For such a large tank, you seem to have very few fish. But now you may have hundreds. Have you tried feeding them? Perhaps they’ll take rotifers.

As quickly as the hatch happened they dissipated very quickly. I don't have setups for rotifers at this time. Perhaps in the future I might attempt to capture and raise the fry.

 

[mort]

do you have any knowledge on the spawning cycles of Pseudochromis porphyreus?

Not specifically porphyreus but I have bred several other pseudochromis and the eggs all hatched on the 4th night, three days after they were layed. This was at 26c. The interval between clutches varied slightly however from 3 up to 7 or 8 days.
That was with pairs rather than harems so I'm not sure whether extra females put more pressure on the males to breed but I know males can have multiple clutches at the same time.

I used to add the larval trap after 3 days of not seeing the male when they were in a more conventional tank, but it was much easier when they were in a breeding tank.

 

[MixedFruitBasket]

Will you tell me what kind of scope set up you have with your cell phone? Brand? Megapixals? I have been looking for something that I can use to do really close up, pretty much near microscopic, photos of details on certain coral specimens.

Thanks