Welcome to Reef2Reef!
Midas Blennies (
Escenius midas) are likely going to be a tough one to figure out how to raise, but I think we can figure out a few things to at least get the community started here.
I have now observed the male showing courtship colors and discovered eggs in one of the PVC pipes and the male is guarding it constantly. Does anyone have any advice on how to potentially collect the eggs
If the eggs are laid on the PVC pipe, then the easiest way to collect them would be by waiting until shortly before they should hatch on the night they're going to hatch (may vary a bit with temperature, but it should be after lights out ~5 days after laying from what I can find), then swapping out the PVC in the broodstock tank for another piece that looks the same while moving the eggs to a larval rearing tank.
These guys should lay eggs pretty regularly (with only a few days between each spawn, from what I can find), so if you don't succeed with this first batch, you should have plenty of chances to try again (and the more info you can get and share here, the better).
Is there a suggested feed like phyto?
Phyto isn't really used for feeding the fish larvae themselves - it's more used to feed things like copepods, rotifers, and Artemia (Brine Shrimp) which in turn are used to feed the fish larvae.
With Midas Blennies, I know that L-Strain Rotifers have been tried without success, and with other blennies of the same genus (
E. bicolor and
E. gravieri), I've heard of S-Strain Rotifers and
Apocyclops panamensis copepods being used unsuccessfully as well. Given that the larvae are way too small for Artemia nauplii and that the only species in the genus which I can find has confirmedly been reared so far is
E. gravieri (reared by ORA), I'd guess it's safe to assume these need either difficult feeders, or feeders not generally available to hobbyists.
So, a good place to start would be with
Parvocalanus crassirostris (cultured with/fed
Isochrysis galbana/T-Iso), and if that doesn't work there are a few more that can be tried (like
Oithona colcarva), but they're a lot more work to get a culture of because they're not sold as individual cultures to the public.
Here's my advice for this - a quick summary, then the more detailed stuff:
-Setup a little, simple tank.
(The larval rearing tank).
-Add the larvae.
-Add the larval food and enough phytoplankton to tint the water green.
(The phytoplankton helps dim the lighting so it's not too bright for sensitive larvae, it makes it easier for the larvae to see the feeders, and it gutloads the feeders so they're more nutritious when eaten).
-Adjust feeding as needed as the larvae grow; you typically should start feeding regular fish food in addition to the larval food around settlement.
Now the detailed stuff:
For a very simple larval rearing tank, take a container, put saltwater in it, add an airstone/gentle sponge filter, and - if needed - a heater that is blocked off by a fine mesh (preferably less than 40 microns).
Some larvae may need more than just room-lighting/ambient lighting too,
For an example of a simple larval rearing setup:
Hi, Im going to post a breeding guide of palaemon elegans shrimps here. Two females are preparing for spawning so if you are interested you may want to stick with me. This breeding guide will be interchangable for every kind of shrimps but i stick elegans because: - With cleaner shrimp we are...
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-You need larval food cultures; in this case, that means small copepods like Parvocalanus crassirostris or similar.
-You need some small sieves/screens (like 45-50 microns or so) to feed only the tiniest pods at first, and you'll need to move up sizes to allow bigger pods as the fish grow. Eventually, you can transition them to larger foods like BBS and/or small pellets (like TDO Chromaboost or Otohime pellets).
It's definitely work to do, but attempting (succeeding can be a different story) to rear the larvae isn't too complicated if you can maintain the feed cultures (pods/rots/BBS and phyto).
(I really need to get around to organizing this info one of these days.)
"Some general advice that might help:
- Have a tank ready to move the larvae into (basically a tank with an air stone, a dim light, and a heater - a kreisel tank is ideal, but not necessary; you don't want a filter, a skimmer, uncovered pumps/powerheads, etc. - it needs to be as pelagic larvae safe as possible).
- Be prepared to catch the young when they hatch (ideally, you'd be able to move the eggs immediately before hatching into the new tank, but I'm assuming you don't know exactly when they'll hatch) - catch them and move them into the larval rearing tank as soon as possible.
Assuming you have fertile eggs, the advice I would give is this:
- if possible, get some Parvocalanus crassirostris pods too (rotifers are great, and I would expect the larvae to go for them, but some fish larvae are picky and prefer pods over rotifers - having both seems like a good way to ensure you have good, small foods for them, and Antennarius pictus was cultured using Parvocalanus nauplii, so it seems likely to be a good food source for them). Artemia and other larger pod species would likely be good to have on hand too for the larvae as they grow.
- Get various sizes of very fine sieves so you can control the size of the feeders being offered to the larvae as/if needed.
- Add phyto directly to the larval rearing tank. It’s a good method of ensuring that the feeders are gut-loaded and healthy, and it makes them easier for the fish to see (better feeding/survival rates are typically observed with this method).
- Observe and note information about the larvae (things like how big the eggs are, how big the larvae are, when the larvae settle, when coloration comes in, etc.) and the larval behaviors (stuff like if they are attracted to light, how they react to light, if they are attracted to certain colors, what feeders they eat and what what sizes of feeders they eat at what days post hatch, what kind of substrate they prefer to settle on, are they cannibalistic, etc.).
- Watch for developmental bottlenecks and issues with your rearing methods.
- A lot of people run into feeder issues their first few times breeding, so I’d have a backup plan in place to be able to get some feeders quickly if you find yourself needing some.
With regards to the sieves and feeder sizes:
- You may need to screen the feed initially to only offer Parvocalanus nauplii.
- Observing the larvae eating when/if possible is important for telling if they are accepting/able to eat the food you are offering them.
And to explain the sieving/screening of nauplii to feed:
Yeah, you'd need to screen the Parvocalanus culture prior to feeding them so that you're only offering the baby Parvocalanus pods (the 1st stage nauplii) to the fish larvae. This is what I was meaning when I brought up sieving the culture if the feeders were too large.
Adult Parvocalanus pods get up to 400 microns, whereas stage 1nauplii are about 40 microns. This means that they should be ~1/10 the size of the adult pods (which looks like it would fit with the ~20% gape rule). So, basically, before offering the feeders to the fish, strain them through a 45 or 50 micron mesh - this ensures that you're only getting the smallest available feeders (those that are small enough to fall through a 45 or 50 micron mesh), which should be more appropriately sized for the larval fish.
Generally the main thing to watch for at this stage is a bottleneck where the young start dying off - these usually happen after a few days (day three post hatch seems to be one of the most common bottleneck days for fish that hatch with a yolk they can feed off of - if the rots and phyto don’t provide the proper nutrition for these guys, you might see a die off sometime around here). Some fish run into multiple bottlenecks, including some that happen around/after 2-3 weeks post hatch, so you really need to keep an eye on how things are going. Bottlenecks typically occur because the food the fry is eating isn’t nutritious enough for them, or they’re not interested in eating the food offered, or the food isn’t the proper size for them to eat.
if you do run into a bottleneck and lose this batch, don’t get too disappointed by it - this happens frequently in trying to breed a new species (even to the professionals), and every attempt gets one step closer to success.
With regards to the substrate settlement:
- Some species need sand, rock, dark areas, specific colors, or other oddly specific things to settle on/in (from what I've seen, inverts are usually a lot more picky with this), so it may help to have a ledge or cave (PVC should be fine for this, if it's even needed, which I honestly kind of doubt) and a little sand in the larval rearing tank.
That’s all I can think of at the moment - hope it helps!"
This last link gives a bunch of info on rearing difficult species and trying to troubleshoot problems with the rearing:
Hey all, So I have a breeding pair of sunshine chromis in my reef tank. They have laid 3 batches of eggs that I’ve seen so far, and by the third day, all the eggs are gone (I’m guessing the snails knock them off or my purple tang eats them). I managed to collect and hatch a handful from the...
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As an important note, Midas Blenny larvae seem to hit a bottleneck ~2 days after hatching, so if you see a mass mortality around then despite feeding properly sized Parvocalanus pods, that's probably a good indicator that they're either not feeding on the pods, or not getting proper nutrition from the pods - while it would be disheartening, this would be fantastic information to share and try and build off of.
Good luck, and please keep us updated on how it goes!
