Hara jerdoni observations and discussion

  • #1
Hello! I would like to catalogue my observations with Hara jerdoni, the moth catfish/Asian stone catfish/dwarf anchor cats.

I have 4 dwarf cats in a mature 6 gallon aquarium, heavily planted, with driftwood, 1 assassin snail, 1 mystery snail, and about 40 cherry shrimp (skittles).
I only ever see 3 cats at one time, so the fourth catfish may be dead - however, it is extremely hard to say for sure, as they are very small and hide during most of the day.

The catfish perch during the day. They have favorite positions (the driftwood, a specific area beneath the lava rock, the dwarf lily petals, or inside the green jungle). They also remain around the section of leaf litter in the tank. However, they will occasionally perch on other objects, especially the filter, scrounging for extra food.


It is said that you should feed this species after dark, as they are nocturnal. I have found this not to be true - they will eat at any time of day, but are normally only active at night. When they are active during the day, it means that they are hungry.
I have slowly trained the catfish to come to a specific area for feeding, and I always feed them at the same time every day. The lighting is a 24/7 cycle, simulating moonlight around 6pm. I feed during the moonlight cycle. Before feeding at the same time, several catfish were not being fed, and were skinny/unwell as a result.
They eat in small bursts, and will often freeze in place after eating - you will see them swallowing/chewing, and they will rest before getting more food. Sometimes in strange positions.
I have also seen them try to eat the shrimp's food (spinach, algae wafer), so I think that they are more aware of food in the tank than I gave them credit for. But they have trouble getting it into their mouths sometimes.


Video of catfish eating

What to feed:

They are very picky eaters, this is true, but mostly due to them not recognizing some objects as food. They have extremely poor eyesight, and I have seen them circle the entire tank looking for food that was behind them, or struggling to eat plant roots thinking that they were worms.
Flakes are of course out of the question. They also do not recognize sinking pellets as food - I have tried bug bites and carnivore pellets, to no avail. They only accept live food (daphnia and brine shrimp or their eggs) and frozen bloodworms.
However, they also have trouble getting bloodworms into their mouths. Occasionally, I will see a catfish try and fail to swallow a worm, only to leave without eating. Smaller pieces are more successful, but occasionally they will spit the worms out for no reason. I have the best luck feeding a clump of worms at once, and each catfish will get about 1 or 2 worms from the bunch.

They are very shy and I have seen the shrimp steal their food. Sometimes they fight back, but sometimes they go without food. This is something to keep in mind. I am happy to feed a big clump, as my shrimp & snails clean the aftermath up.

How often to feed:
I couldn't find an answer to this online, but I have experimented with different amounts of food. Initially, I fed the entire tank a huge clump of bloodworms 1 or 2 times per week. My catfish were skinny, and some were losing skin, but each would come for feeding.
Now I feed every other day, but only 1 or 2 catfish come to feed each time. They probably don't need to eat more than once every three days, but because they sometimes do not eat when the food is out (cannot find the food, cannot get it into their mouths, spit the worms out), they may go hungry if not fed more often.
Every day, I will spritz the tank with a few brine shrimp, which usually entices them to feast.
It is true that they will turn a more reddish color if live-fed with brine shrimp, and are more active as well.

(The catfish on the right is more red from preferring brine shrimp, while the other prefers the bloodworms).

Losing skin:
This species is very sensitive, and will shed their skin if the conditions are not right. My tank is maintained by a 10-20% water change each week, with substrate cleaning of the feeding area. No nitrites or ammonia, and 5ppm nitrates. The pH is high, but I have been eternally struggling to get it below 8. It is 7.8 now, and as low as possible, even using distilled water & peat treatment. However, while the catfish do prefer acidic water, they have slowly acclimated to the alkaline water and are fine. Google says that up to 7.8 is possible for this species.

This is an individual that recently shed part of its skin. You can see a missing patch from the dorsal fin, and some bare parts among the side.
However, I figured out that this is the fish that does not easily eat bloodworms. It is the reddest of my three, because it only really eats brine shrimp. Since feeding more live food, it has slowly begun to regain its skin.

This species has sexual dimorphism, but it is very hard to tell males and females apart. Supposedly, they are a very social species and prefer groups, but I rarely see the catfish next to each other, which has made it hard to compare sexes.
The females are larger, with a rounder abdomen. They also have shorter tails and a rounded dorsal fin, while the males have a pointier dorsal fin.

To return to this image, the fish on the left is female, and the one on the right is male. The third catfish I think is female, and the fourth I think is male, but I have never seen all 4 in the same place at the same time.
Breeding is considered extremely difficult - I haven't had luck yet. But I was told to try doing a large water change and replacing with cold water to simulate rain. The catfish were much more active afterwards, but no breeding yet.

Red stomaches:
I have noticed some red patches on the stomachs of my fish occasionally. My theory is that this is their stomach showing through their skin - either when they are full or hungry.
I am leaning towards hungry, because I notice them more when the fish are swimming erratically (which they do when they are hungry).
The spots were much more prevalent before I started feeding more often, and in this (old) photo you can see shed skin as well, so it may be a stress indication. Currently, the cats have very small red spots.


There you have it! The only true nano fish, capable of being in a tank as small as 3 gallons. They are very cute and not too difficult to take care of.

Edit:I finally saw all 4 of them at the same time while writing this, so all of my cats are alive and well :)

86 ssinit
  • #2
Have you tries freeze dried tubifex worms. Id take a cube cut it in half or smaller. Take a piece and put it in water. This will separate the worms. Then spill some in and see if they eat it. These are smaller worms so should be easier to eat.

  • Thread Starter
  • #3
Have you tries freeze dried tubifex worms. Id take a cube cut it in half or smaller. Take a piece and put it in water. This will separate the worms. Then spill some in and see if they eat it. These are smaller worms so should be easier to eat.
I have tried those! They unfortunately don't sink to the bottom, so my guys arent able to eat them
86 ssinit
  • #4
Soak them first
  • #5
A coral feeder might be of use, if getting lightweight food directly to them is a concern going forward.
  • #6
Nice write up. Thanks for sharing.

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