Show me your pineapple fish!

davidcalgary29 · Nov 11, 2022

Okay, I was exploring a tangential comment made by @Jay Hemdal about the susceptibility of marine fish to ich with different types of scales, and thought "well, what about fish covered in scutes?" And that led me to pinecone fish, and, specifically, pineapple fish, which are apparently "popular" with aquarists. What?

Someone here must keep them, right? I'm just trying to imagine a group of weak swimmers hanging around the same rock ledge for seven years.

Jay Hemdal · Nov 12, 2022

davidcalgary29 said:
Okay, I was exploring a tangential comment made by @Jay Hemdal about the susceptibility of marine fish to ich with different types of scales, and thought "well, what about fish covered in scutes?" And that led me to pinecone fish, and, specifically, pineapple fish, which are apparently "popular" with aquarists. What?

Someone here must keep them, right? I'm just trying to imagine a group of weak swimmers hanging around the same rock ledge for seven years.

There are two species of pinecone fish that show up in the trade from time to time. Both are actually VERY susceptible to ich. They require cooler water overall, and I haven't seen very many of these since before Covid.

Here are two excerpts from my Advanced Marine Aquarium Techniques about them:

Pinecone fish (knightfish)
Cleidopus gloriamaris
Maximum size: 20 cm
Habitat: Rocky reef caves
Range: West and East Australia (but not the cooler Southern waters)
Although not often imported in recent years, in the past, this peaceful fish had been available from this region in limited, but consistent numbers. They are compatible with almost any other species of fish, and have even been kept with chambered nautilus, flashlight fish and cuttlefish. This species possess a light organ below each eye filled with colonies of the luminescent bacteria, Vibrio fischeri. Avoid treating these fish with antibiotics or copper medications if you wish to keep these bacteria glowing brightly. They sometimes require live foods such as guppies or adult brine shrimp to start feeding, but some adapt to non-living foods such as small krill and diced seafoods.

Pinecone fish
Monocentris japonicus
Maximum size: 15cm
Habitat: Rocky reefs from 10 to 200 meters depth, 50 to 65 degrees F.
Range: Red Sea through the Western Pacific
Aside from shipping costs, pinecone fish seem to be relatively inexpensive from Japanese collectors as opposed to those in Australia or elsewhere in this specie’s range. One collector offers small specimens (not including shipping charges) for 1400 yen, or less than $15 US at the time of this writing (2005). Hardy and peaceful, pinecone fish may be slow to begin feeding, and live brine shrimp may be required as a starter food. Acclimated specimens feed readily on frozen mysids and small krill. If kept in dim aquariums, and kept sufficiently healthy, you may be able to observe this species luminescent bacteria pockets that glow green beneath each of its eyes.

Jay