Care for juvenile Cynops pyrrhogaster (Japanese firebelly newt)

The challenge.

C. pyrrhogaster metamorphose at a rather small size, generally about 1 inch (2.5 cm). Because of their small size and general refusal to stay aquatic, the juvenile period is the most difficult in the care for this species. Keeping them healthy requires a balance between the animal’s comfort versus ease of feeding and monitoring.

This article is based on my experiences only: “your mileage may vary.” Most of this article also applies well to how I raise juvenile C. ensicauda.

Foods. At various times, I have used the following foods:

Live blackworms. These need to be kept in a shallow dish. Adding some tiny pebbles will help keep the blackworms from crawling out. It also helps to use a dish with steep sides. However, care must be taken to allow the newtlets to get out easily. Also, when blackworms escape onto soil, they will die and foul the soil badly; this can be deadly.

Fruit flies. These are taken readily. The main difficulty is that they tend to escape the enclosure. It is helpful to use a piece of cloth to cover the enclosure in order to prevent this. They should be dusted with a good quality vitamin/mineral powder every second or third feeding.

Springtails. It’s been documented that wild C. pyrrhogaster juveniles eat a diet primarily of springtails. Springtails are very easy to culture. However, they are a very tiny food, and a lot of them need to be provided in order to keep the juveniles decently fed. Also, as the terrarium ages, springtails may overrun the entire enclosure.

Small earthworms. These are undoubtedly the best “growth food”. They can be served chopped (still wiggling) in a shallow dish, or offered by hand-feeding. It doesn’t work very well to simply drop them whole into the setup, as they will burrow and hide very effectively.

Pinhead or very small crickets. Be careful not to overdo these. If present in excess, they may bite the newts or cause general stress. They should be dusted with a good quality vitamin/mineral powder at every feeding.

Live whiteworms. These are easy to culture and are accepted readily. However, they do not provide the nutrients necessary to develop an orange belly. They either need to be used in moderation, or they need to be supplemented with carotenoids.

Frozen thawed bloodworms. These can be hand-fed with tweezers. Some keepers have succeeded in training metamorphs to eat them from a glob placed on a cap in the enclosure.

Hand-feeding. One option is to train the metamorphs to hand-feed. This is tedious and requires NOT offering any live food. Very tiny bits of chopped earthworm offered on a toothpick are usually used. Once trained, other foods, such as frozen bloodworms can be offered.

Juvenile C. pyrrhogaster with dinner (a blackworm). After metamorphosis, firebellies go through a terrestrial phase. Mine would eat from a shallow water dish, but would not go into deeper water until they reached one year of age.

Housing. This may seem odd, but the animal’s setup needs to be designed around the type of food that is being given. If live blackworms are being used, then there needs to be a bare area where escaped blackworms can be caught before they foul the soil.

I prefer soil that retains moisture well. I use a mixture of coconut fiber (Bed-a-beast, or other brands, usually sold in a brick) and bagged top soil from Walmart. I keep some damp moss in at least part of the setup. I use non-live moss soaked in several changes of water before use.

If fruit flies are being used, it is helpful to use a lid that prevents the fruit flies from escaping. Putting a piece of cloth or mosquito netting under the lid or screen should do the trick.

Example of a type of setup I have used for newly-morphed C. pyrrhogaster. When in use, a tight-fitting lid (with holes) covers the cloth. A large bottle cap in the center is used to hold food (springtail culture, live blackworms, or small chopped earthworms).

Semi-aquatic or terrestrial? I have had poor luck trying to keep juvenile C. pyrrhogaster semi-aquatic during the first year. They will usually refuse to go into any water deeper than “wading depth”. I and others have lost individuals to drowning, even in setups with less than an inch of water and plenty of easy access to islands. In one case, I was keeping several metamorphs in a very shallow setup. One day, I observed one of them swimming (seemingly quite happily) in the water; the next day that individual was dead in the water, presumably due to drowning.

I should mention that other people have had success keeping this species semi-aquatic, so it can be done. I should also mention that other Cynops that I have raised (cyanurus and ensicauda) or read about (orientalis) seem to be much more willing to adapt to semi-aquatic setups after metamorphosis.

Another setup I have used for juvenile C. pyrrhogaster. The animals shown are about 1 month post-morph. The water dish contains pebbles and live blackworms; the piece of plastic over it makes the juveniles more likely to spend time, as they feel hidden there. When closed, the tub has a piece of cloth (to keep in the fruitflies) and a tight-fitting lid with holes.

Note: tight fitting lids prevent escape. The plastic has many small holes for ventilation. The cloth inside the lid prevents fruit flies from escaping and prevents gnat from invading.

When will they be aquatic? In my experience, they are ready and willing to venture into water at one year post-metamorphosis. Even ones that have grown very little in the first year will often be willing to take to water at this point.

They need to be introduced gradually to shallow water with plenty of resting places. Live plants are particularly useful in this regard. Once aquatic, they will take a much wider range of foods. If they get live blackworms or bloodworms, they will grow rapidly from this point on.

Climbing. Juvenile firebellies are excellent climbers. Whatever housing is used, it should be absolutely secure from escape. To some extent, their climbing can be used as a barometer for their level of contentment with the setup. If you observe them climbing nearly all the time, you should consider the possibility that there is something wrong with the setup. It could be a lack of hiding places. It could be that the substrate is too wet or too dry. It could be a lack of food, or irritation from excess live food present. It could be an infestation of the soil with excessive springtails, mites, or fungus gnats. These critters are not harmful, but can be irritating in large numbers.

Size differences. At any point in development, it is common for some individuals to grow much more rapidly than others. This becomes a problem for two reasons. First, the largest ones may actually grow big enough to eat the smaller ones. Second, the largest ones will invariably eat faster than the smaller ones, thus causing the size difference to become more and more pronounced over time. The smaller ones may even starve. There are two solutions to this problem. First, you can separate the group based on size. Second, you can feed often with over-ample amounts of food so that all get a chance to eat. However, overfeeding can result in fouling the enclosure and other problems. Some individuals are naturally shy and simply may not survive under the conditions offered.