Dartfishes Breeding/Spawning Overview - Ptereleotridae

[mpedersen]

Ptereleotridae - Dartfish - Breeding, Mating, Spawning and Rearing Overview

1 - Species covered in this forum:

The Family Ptereleotridae - This family includes popular species such as:
Nemateleotris decora - the "Elegant" or "Purple" Firefish
Nemateleotris helfrichi - the "Helfrichs' Dartfish" or "Helfrichi Firefish"
Nemateleotris magnifica - the "Fire Goby" or "Firefish"
Ptereleotris evides - "Scissortail or Rocket Goby", or "Blackfin Dartfish"
Ptereleotris zebra - "Chinese Zebra Goby" or "Bar / Barred Goby"

For an overview of the Ptereleotridae, see http://www.fishbase.org/identification/ ... &areacode=

2 – Common characteristics:
For such a popular group of aquarium fish, surprisingly little information is available regarding their reproduction. Reports on breeding almost seem like apparitions, everyone seems to know someone who's "bred" their dartfish, yet no one has raised any, and the sparse details on observed reproductive behavior vary wildly from account to account. Dartfish represent a great opportunity for those individuals who wish to try something different and make a valuable contribution of knowledge to the marine ornamental breeding community.

The Dartfish are all share an elongated body structure. They are all planktonic feeders. Most species are typically found as pairs as adults, although some species naturally occur in groups. Most all species typically have a "bolt-hole", a burrow or hole in the substrate that they are never far away from. Several species are deeper water species, which explains at least part of their higher price (especially in the case of the Helfrichi Firefish).

For more basic information, visit - http://www.wetwebmedia.com/dartfish.htm

3 – Reproduction:

3.1 – Sex determination:
Unknown

3.2 – Sexual organization:
Pairs - probably monogamous pairs. Many of the species in this group are routinely found as pairs in the wild. In Nemateleotris, juveniles may be found in groups, but aggression sets in upon maturity.

3.3 – Sexing:
There does not appear to be any reliable means of outwardly sexing a dartfish. Pairs appear to be sexually monomorphic and sexually monochromatic. Observations of intraspecific behavior / interaction is most often the "key" to identifying a pair. Within an actively reproducing pair, you may be able to identify the sexes during the pre-spawning period when the female "ripens" and becomes swollen with eggs.

3.4 - Pairing / Setting Up Broodstock:
First, the Firefish, genus Nemateleotris. One species, Nemateleotris helfrichi, is routinely available as compatible pairs. It is not known whether this compatibility is the result of a true male / female pair, or if this species is simply one of the less aggressive Firefish. Nemateleotris decora is the most aggressive of the firefish - it may be difficult to form a pair. Nemateleotris magnifica is the most commonly available Firefish, and is the one most likely to be housed in a group while in a local fish store's aquariums.

When settled in, observing the fish at length may help in picking a pair. You may find an obvious pair who spends their time together, away from the group, or even bullying the rest of the group. If you're real lucky, you may even find a pair sharing a bolt-hole.

If not, pay careful attention to intraspecific aggression. Identify the "top dog" or bully in the group and watch how it interacts with others. Fish which are approached in an aggressive manner may be the same sex as the aggressor. Fish which are approached and "displayed" to may be fish of the opposite sex. Of course, it may take a while until you can pick out your two prefered fish out of a group of 5 or 6.

3.5 – Courtship:
Unknown

3.6 – Spawning:
Conflicting information suggests nothing is necessarily reliable. One report suggests spawning in a depression in the substrate. 2 other plausible scenarios involve spawning in caves, with at least one suggesting an egg ball. Tending may be done by both broodstock partners.

Spawning frequency is not solidly known, and may vary, between every 8 to 28 days.

4 – Eggs:

4.1 – Size:
Unknown

4.2 – Quantity:
unknown

4.3 – Characteristics
Include items like egg shape, color, are there oil droplets (and if so, how many), are the eggs boyant or do they sink, are they adhesive? List out by species if appropriate

4.4 – Incubation period/Hatching temp:
References suggest 7-10 days.

5 – Larvae:

5.1 – Size at hatching: unknown
5.2 – Yolk sac present at hatch: unknown
5.3 – Mouth present at hatch: unknown
5.4 – Eyes developed at hatch: unknown

6 - Rearing:

6.1 - Breeding & Rearing Techniques
Unknown. Efforts with greenwater techniques were unsuccesful with Ptereleotris zebra beyond 10 days.

6.2 – Day at first feeding:
Unknown

6.3 - Starvation Time:
If known, include the time post-hatch that larval will live without feeding. This can often be found in larval studies where scientists do not feed the larvae, as well a accounts of failed larval rearing attempts.

6.4 – Feeding scheme:
First Foods, progression, whatever is appropriate based on current information and experiences. List any special techniques / timelines available.

6.5 – Age at meta:
Unknown, but it's rumored that there is a substantial larval period and that there may be some special settlement cues.

7 – Species been reared successfully
Rumors are everywhere, but haven't seen any Captive Bred Firefish!

8 – References

8.1 - Articles

Schiller, Guenter, Spawning Behavior of the Decorated Firefish, 1990, SeaScope, Volume 7, Fall 1990. Aquarium Systems, Mentor, OH, 44060, ISSN 1045-3520 - online at http://www.instantocean.com/uploadedFil ... 7_1990.pdf

8.2 - Web Content

Breeder's Registry Report on Nemateleotris decora - http://www.breedersregistry.org/database/NEMDEC01.htm

Article mentioning rearing attempts for Ptereleotris zebra - http://www.gobiidae.com/breeding_c_pers.htm

Web Post including spawning information - http://www.fishforums.net/content/Saltw ... fish-Goby/

8.3 - Books
List any books that contain "Breeding-Relevant" information to this group.

9 - Compiled By
Matt Pedersen - mpedersen / mwp - matt (at) cichlidrecipe.com
Last Update: 1/24/2008