Breeding the Hong Kong Warty Newt, Paramesotriton hongkongensis
by Louise Selfridge
Introduction
My experience as a newt keeper started in the early 1980s, and was a logical progression from tropical fish keeping. In those days, reptiles and amphibians were coming into vogue as pets, and most examples found in pet shops were sick, stressed wild-caught individuals.
I had, as a 12-year-old, purchased two Japanese fire-bellied newts (Cynops pyrrhogaster), which survived very happily in a semi-aquatic aquarium on earthworms and slugs I harvested from the garden. I then progressed to a spotted salamander (Ambystoma maculatum) and some oriental fire-bellied toads (Bombina orientalis).
My interest in newts was rekindled in the early part of 2007, when a friend sent me some Axolotl eggs to raise (Ambystoma mexicanum). On a visit to the aquarium shop to buy them some Daphnia, I saw a small aquarium full of what were described as "dog-faced newts". They all looked healthy, so I decided to buy four and put them in the aquarium I had cycled ready for the axolotl larvae.
The First Breeding
The first time that the newts bred was a surprise. The morning after purchasing
them I noticed a couple of the newts were grasping the plants and laying
eggs. I removed the eggs and added plastic strips for egg-laying. Unfortunately,
the newts seemed to prefer laying eggs on the plants, so I went out and bought
some more. Elodea and Amazon sword plants (Echinodorus amazonicus) were
the favoured species.
The egg-laying behaviour started at the beginning of March and continued for a few weeks, and altogether I harvested about 200 eggs, some of which I gave away to friends. I kept the eggs in a plastic tub with a small air stone, and changed the water every couple of days. As they developed, I moved them into fish hatcheries in the parents' aquarium. They started to hatch about 6-8 weeks after laying, towards the end of April, and most of the larvae were very healthy and robust. The water temperature was in the range of 18 - 25°C.
Raising the Larvae
I lost approximately 10 of the larvae within the first few days; they
appeared to be either deformed or premature. In total, about 80 larvae
survived. The larvae are much larger than a lot of other species, and
they are able to consume bloodworms and Daphnia at hatching. I didn't
use brine shrimp (Artemia) because I didn't want to risk fouling the water.
On a few occasions, I observed cannibalism - a larva would completely
swallow one of its counterparts, but because they were so big, it took
the best part of a day to swallow.
Two months after they had hatched, about the beginning of June, I moved all of the larvae from the fish fry nurseries in which they lived in the parents' aquarium into a small aquarium of their own. I placed one end of the aquarium on a block to give it a natural slope, and partially filled it with water, leaving the raised end dry. I put a damp paper towel into the dry end. At this stage, the larvae were still eating live and frozen bloodworm, with some Daphnia and frozen blackworm (Lumbriculus) for variation. The temperature was roughly 18-25°C (64-77°F); they were kept in my kitchen so the temperature fluctuated somewhat.
My first larva metamorphosed at the beginning of July, almost three months
to the day after hatching. It crawled out of the water onto the damp paper
towel, and waited there until I picked it up and transferred it to its
new terrestrial home. I noticed that just before it left the water it
shed its skin. I had been anticipating the metamorphosis, as a few days
before I noticed various subtle changes in a few of the larvae:
- Their heads looked broader and flatter.
- Their tails were thinner.
- They had started to develop little orange spots on their bellies.
- Their gills were shrinking.
- The yellow extremities (tail, eyes, and gills) had darkened to almost black.
Post-Metamorphosis
As the larvae metamorphosed, I moved them into plastic tubs with damp
paper towels and moss. I fed them on pinhead crickets, and they ate well.
Of the 80 or so larvae I had at the beginning, I ended up with around
45 metamorphs. These young newts have been very easy to care for, contrary
to the stories I had heard about problems with this genus post-metamorphosis.
In a year, I lost one juvenile, which wouldn't eat and starved to death.
The juveniles are still doing well, and although they eat tiny crickets, tropical white woodlice, live bloodworms and tiny earthworms, they grow very slowly.
The Second Breeding
A year later, my Paramesotriton hongkongensis have had another bumper
breeding season, through no effort of my own. The first year seemed too
labour intensive and expensive, so I had decided to leave the newts to
rest for a year. However they had other ideas.
They are housed in a 1.5 foot (45 cm) long aquarium with a photoperiod of 12 hours. Their light is set to come on at 8 am and go off at 8 pm. They are kept in my kitchen, which is fairly cool, but as mentioned earlier, the temperature can fluctuate somewhat between day and night, and depending on whether I'm cooking or not (18-25°C; 64-77°F).
They have a small Fluval filter, an air stone and some rocks in the aquarium, as well as lots of Elodea, Amazon sword plant and Cabomba. I keep an eye on the water quality, but I don't carry out water changes weekly. The adult newts are fed on earthworms, waxworms, frozen bloodworm and amphibian pellets.
At the beginning of December, I noticed that my newts seemed quite restless, and were very active despite the cooler time of year; in winter the temperature in my kitchen is about 10-15 °C (50-59°F), and occasionally even cooler at night. The male had developed an impressive white tail stripe, and the females were looking very plump. This surprised me, as I had done nothing to cool or otherwise condition the animals for breeding.
Throughout December, January and the early part of February, the females laid a large number of eggs. I saw the male tail-fanning several times, and observed a couple of spermatophores, but his input seemed minimal. The egg-laying tailed off toward the end of February, and only at the beginning of March did the male's white tail stripe begin to fade.
I removed the eggs and put them in a tub like the one I used the first year, but many of the larvae hatched prematurely, just after the tail bud stage. This hadn't happened the first year. I put the premature larvae into fish fry nurseries in the parents' aquarium, and they developed into healthy, full-term larvae. Most of the eggs hatched around a month earlier than last year. The larvae looked good, and fed voraciously on live bloodworm and Daphnia. There was quite a variation in the size of the larvae, and I put in plenty of vegetation in which they can hide. When I removed the vegetation to clean, the larvae seemed rather stressed, and tried to "hide" under each other in the corners.
Five months later at the time of writing this article, I have around 24 juveniles. I hope that I can repeat the success I had the first time! I lost a few metamorphs in the early days. I don't know why they died, as they seemed very well fed. Ironically, the last larva to metamorphose (it metamorphosed at the beginning of June!) died the following day, in spite of its large size and healthy appearance.
Conclusion
As a relatively inexperienced newt keeper, I am surprised at how easy
it has been so far to keep and raise these beautiful newts. It has cost
me a small fortune in live foods, and the water changes and maintenance
have been labour-intensive. However it has all been worth it, and I hope
that captive bred populations can ease the pressure on wild newts.
Warty newts may not be the most flamboyant or attractive caudates, but
they are full of personality, and a joy to keep!
Louise Selfridge is a primary school teacher living in Glasgow, Scotland. She regards herself as a fairly inexperienced keeper, and although she kept caudates in her early teens, that passion has only recently been rediscovered. Along with Paramesotriton hongkongensis, she keeps axolotls and several species of Tylototriton. Currently she also keeps juvenile Mesotriton alpestris and Taricha granulosa, as well as Cynops orientalis and Triturus marmoratus.
Article © 2009 Louise Selfridge. Posted on Caudata Culture with permission of the author, January 2011.