It’s mucus, and is a way for them to shed external parasites, fouling growth etc. It comes off in thin sheets that look like cellophane. Most scorpionfish do this, and they are not particularly vulnerable during shedding. They’re usually bright and shiny afterward!

1.) Do the babies need to be separated from the parents?

The egg mass was removed from the display immediately, mostly to try to raise the larvae (babies) in controlled conditions. If left in the display tank, all the different filters would harm the larvae. Marine fish start as larvae that float in the soup of the ocean, and take time to develop eyes, fins, guts, and a variety of other body parts. They go through significant changes before “settling out” as juvenile fish. The larvae are very fragile so too much light, too much flow, slightly degrading water quality, and a host of other issues can cause them to quickly leave the land of the living. The eggs were put into a special low-flow tank behind the scenes with no corners (larvae don’t do well with corners) that is kind of like tanks we often keep jellies in. The larvae started out at about 1 mm long, so the parents eating them was really not an issue.

2.) What do the larvae eat, and how is it being provided?

This is one of the stumbling blocks to raising marine larvae – what do they eat? The Rhinopias larvae are especially small, so feeding them is a real challenge, and of course, they need live food. We tried rotifers, a common first food for captive raised larvae, but none of the larvae seemed to have eaten them. While we saw gut action in the larvae around day 6, we were never able to see anything actually in the gut. For the next batch of larvae (we hope!) we will be trying an even smaller food, just hatched copepods (Tisbe spp.) along with anything else we think they might eat.

3.) Since they are rare, are there any plans to release them into the ocean wherever their natural habitat is located?

We were able to keep the first batch of larvae alive for 10 days, which is actually a very good showing for such small animals that no one has ever raised before (and we are prepped and ready to try again!). When we are able to raise them, there are currently no plans to introduce them into the wild due to several issues. It is unclear where these particular animals were collected (they range from the South Pacific to West Africa), so it would be difficult to decide where to actually release them. More importantly, since these fish are kept in water with animals from all over the world, there are issues with released fish carrying diseases that are not native to a particular location, and we would be very much saddened to introduce a non-local pathogen that could potentially decimate local animals. On the plus side, when we are able to raise these fish, we will be able to supply them to other public aquariums, lessening the collection pressure on wild populations.

4.) Can fish get sunburns?

It appears that they might be able to get sunburns. Most fish are able to swim down to areas where getting sunburned is not an issue. Some fish that live near the surface of the water may be prone to sunburn, especially when high amounts of UV are present from ozone depletion or other factors. There are also reports of pond fish chronically resting their heads above water and getting what looks like sunburn.