Black Skirt Kept Alone - Advice?

[shrimp_lass]

Hi!

I recently acquired a new tank on Craigslist... it is a five gallon with two Mollies and one Black Skirt Tetra. I bought the tank for my shrimps, wasn't told it already contained fish.

I know that the black skirt is a schooling fish so I was planning on moving him/her to my 10 gallon when it is done cycling in another week or so, and adding some other black skirts. Anything i should know about introducing this fish who has maybe never been kept with another black skirt? Should i keep the mollies with her and just add 4 more black skirts or am I overstocked at that point? This fish is not skittish at all, doesn't seem to care about the extra hiding spots I've added or anything.

Another thing I've noticed is the way he/she is swimming: between each push with the fins she seems to drift upward and I'm wondering if this is a problem.

Noob questions I know, thanks for any help!

 

[Byron]

Several things here.

First, a 10g tank is not sufficient space for a group of Black Skirt Tetras. This species does get a decent size and needs at least a 30-inch (75 cm) length tank like a standard 29g. A group of six or more in this sized tank would be the best maintenance. But there are other issues here.

Second point is that this fish can get a bit feisty and fin nip other fish. One reason why it needs a group of six minimum but a few more wold be better is that when kept in fewer numbers the fin nipping is increased. But not having space for this, you are left with either keeping the lone fish in the 10g--but no other upper fish will be possible as the fact of keeping it on its own will increase its aggressive tendencies and cause real problems.

So given that, and assuming you do not have a larger tank for this species, rather than get more I would re-home the one. Some stores will take fish.

But that brings up another issue, that if this fish has any problems no store is likely to want it. There are times when euthanizing a fish is the best alternative.

While I'm here, as you mention mollies, they need moderately hard or harder water. GH (general or total hardness) must be 200 ppm (= 11 dGH) or preferably higher.

 

[shrimp_lass]

Thanks so much for your quick response!

As for the 10 gallon, that was my fear. I had it in mind because it was almost there and cycled, but I originally had other plans for it--breeding shrimp for my cichlids. I do have a 40 gallon tall, with rocks and plants and the specs are this:

ammonia: 0
n-ites: 0 (sometimes .125 but hard to tell with the color chart. I have been using seachem prime and 20% wc when I see this.)
n-ates: 0-5
ph ranges from 7-7.2
GH 6-8
KH 1-3
TDS no idear but I do have some limestone in there

Tank has six juvenile honduran red points (1-1.5 inches right now, and the black skirt is about 1.5). No pairs as of yet and minimal aggression, but probably wouldn't be the best place for a school of black skirts especially as the HRPs get older. But, I am planning on selling off any pairs as soon as I see them to keep aggression down. I do want to keep this black skirt and get a good tank for him/her, with sufficient space for a school. But what are your thoughts on putting the six of them in there, short term? Would they just not work? Could I add them all at once with my nitrite problem?

I'll post pictures soon of this black skirt but his/her color is very faded and he/she is very slow. What are your thoughts on giving them to a LFS that just wants her as a feeder? I'd rather not euthanize but as a last resort.

 

[Byron]

My advice would be to re-home the lone Black Skirt. There is no suitable tank in what you write for a group of this species. Cichlids are not good tankmates for fish that tend to nip fins so this would likely create serious problems. Given this fish along with two mollies was being housed in a 5 gallon tank by the person who sold it, the fish is probably highly stressed and this means subject to all sorts of issues. Adding it to a group, or adding a group in with it, of its own could well spell real disaster. Stress impacts fish significantly, and the internal effects are permanent no matter what may occur subsequently. Euthanizing it would probably be kinder to be honest, but that's up to you. What another so-called aquarist did to the fish is not your fault, but you are now faced with resolving it.

Now to the water test numbers. If fish are in this tank, ammonia and nitrite above zero is serious. Daily partial water changes of half the tank volume, using Prime, are advisable. I would also use a bacterial supplement, they do help. Tetra's SafeStart, or Seachem's Stability.

On the Prime. This does detoxify ammonia and nitrite, but this is temporary, not permanent, and both will still show in tests. Prime is effective for 24-36 hours, after which, if the ammonia or nitrite (or both) are still present, they will revert back to their toxic form. Hence the daily WC's with Prime. Ammonia and nitrite testing zero will mean they are gone, whatever form.

On the GH, this is not sufficient for mollies. I assume the 6-8 is dGH (not ppm or mg/l) and this is too soft. The mollies will not do well and again they are already stressed. It would be best to re-home these too. They need a 30-inch length tank minimum, but 36 inches is better. Males can attain 3 inches, females 5 inches with some reports of six inch females. And they are highly intolerant of any ammonia, not to mention nitrite and high nitrate. Using a calcareous substrate, or using mineral salts, would be recommended for the mollies. But if other soft water fish are in the tank, this is not going to work as it then is detrimental to the soft water species.

 

[shrimp_lass]

Yes I did mean dGH. I've attached a picture to make sure they are mollies--this woman had no information about them so that's just my best guess. Could be platies. Also attached pics of the black skirt, who isn't doing the weird swimming thing anymore, seems pretty active and is coming up to the front of the tank when I walk by.

I asked one fish store and they said they would take the black skirt, didn't ask about the mollies just yet. I remember they keep them in pretty smallish tanks there though, and when I asked the guy he recommended keeping three black skirts in my ten gallon (don't worry, I'm not gonna do that). What's the best way to euthanize, if I decide to do that? I'd like to know but I am going to at least sleep on it.

 

[Byron]

I asked one fish store and they said they would take the black skirt, didn't ask about the mollies just yet. I remember they keep them in pretty smallish tanks there though, and when I asked the guy he recommended keeping three black skirts in my ten gallon (don't worry, I'm not gonna do that).

The fish in the first photo is a female platy. All livebearers (platy, guppy, Endler, molly, swordtail) need moderately hard or harder water, so with your moderately soft water the platy will not be at their best though they would manage better than mollies.

As for small tanks at the store, keep in mind that stores are not permanent homes for the fish. They aim to sell them as fast as they can because the longer they keep them the more it costs them and the less they make when they sell them. Nothing wrong in that, but it does mean that temporary tanks are not going to be set up like permanent life-long tanks at home. The fish in the store tank will be under severe stress most of the time from various environmental issues (tank size, too many, other species, no decor/plants to provide cover, perhaps insufficient water changes). Once you get them home, you are providing what will be their final home until they die, and that must accommodate what the fish species expects if they are to be healthy and happy.

What's the best way to euthanize, if I decide to do that?

Net the fish out and place it in a couple of paper towels folded over, then quickly fold the towel completely around the fish, and lay it on a hard surface like a counter top and give it a couple whacks with your hand. Some recommend a mallet/bat, but I use my open hand. This will instantly kill the fish; no suffering beyond normal netting. This is the most humane and quickest way; an article in PFK a couple years ago listed this method as #1 with no suffering for the fish.

 

[shrimp_lass]

Thanks again for your quick reply, sorry mine is not so prompt.

So, I’ve decided not to euthanize. I got a new tank, a 55 this past weekend and it’s now set up, just waiting for it to cycle—the guy I bought it from says he has had fish in it until recently and has kept the filter going, so I’m hoping that will jumpstart the process. I also threw in a bit of filter media and lava rock from two of my cycled tanks. I am planning on moving my cichlids to that tank and leaving the 40 to get a group of black skirts, at least 10 to start.

My plan for introductions, feel free to add to this or correct me: get fish as similar looking to mine as I can and float them and release them in the dark, gradually moving to dim light on one side of the aquarium. As for the two platies I will keep them where they are and see if anyone can take them.

Thanks again for all your help!

 

[shrimp_lass]

Thanks again for your quick reply, sorry mine is not so prompt.

So, I’ve decided not to euthanize. I got a new tank, a 55 this past weekend and it’s now set up, just waiting for it to cycle—the guy I bought it from says he has had fish in it until recently and has kept the filter going, so I’m hoping that will jumpstart the process. I also threw in a bit of filter media and lava rock from two of my cycled tanks. I am planning on moving my cichlids to that tank and leaving the 40 to get a group of black skirts, at least 10 to start.

My plan for introductions, feel free to add to this or correct me: get fish as similar looking to mine as I can and float them and release them in the dark, gradually moving to dim light on one side of the aquarium. As for the two platies I will keep them there for now. May have someone who can take them in. Any suggestions for how black skirts like their decor? I have plants and driftwood in that tank now but I may move it over to the 55 with the cichlids.

Thanks again for all your help!

 

[Byron]

While all hobby fish of this species (Gymnocorymbus ternetzi) will be captive bred unless you acquire them from a source that imports wild caught fish, the species' requirements are still in their DNA so knowing the habitat environment allows us to provide the best home.

This species is native to the basins of the Rio Paraguay and Rio Guapore, Bolivia to northern Argentina. It is found in small slow-flowing creeks and streams, usually with dense overhanging or floating vegetation.

A fairly active species when young, it likes some swimming space in a planted aquarium; floating plants are also recommended, along with subdued lighting to bring out the best deep black colouration. As it matures, it becomes less active. It will occupy all levels in the aquarium.

So a tank with plants around the sides but open swimming space is one option. Another which is more true to the habitat would be sand substrate, several branches and/or chunks of wood, some vertical around the sides and back, and floating plants which replicates overhanging marginal vegetation under which the fish live.

 

[shrimp_lass]

Agreed, I want to buy some water sprite and let it float to provide cover. The 40G tank as it is now is in front of a window (east facing, never direct sunlight, never hot or drafty) and I don't use artificial lights for this tank. This is something I tried for my cichlids when I went out of town for two days, and when I came back their colors were more vibrant! The window light is more subdued than the lights I had been using. I like the natural light and gradual light changes and have had no trouble with algae. So maybe I'll continue with that, unless you see an obvious problem I'm missing? But I've been toying with the idea of doing artificial light over half the tank and having either water sprite or lettuce grow underneath that.

 

[Byron]

Agreed, I want to buy some water sprite and let it float to provide cover. The 40G tank as it is now is in front of a window (east facing, never direct sunlight, never hot or drafty) and I don't use artificial lights for this tank. This is something I tried for my cichlids when I went out of town for two days, and when I came back their colors were more vibrant! The window light is more subdued than the lights I had been using. I like the natural light and gradual light changes and have had no trouble with algae. So maybe I'll continue with that, unless you see an obvious problem I'm missing? But I've been toying with the idea of doing artificial light over half the tank and having either water sprite or lettuce grow underneath that.

Using natural daylight from a window is very risky. First, it will usually not be sufficient for aquarium plants if there are any; Water Sprite for example will not last without reasonably good overhead lighting because being fast growing it has a high light and nutrient requirement. I tossed some in my outdoor pond last summer and it did very well even with no fish or plant additives.

Intensity will vary from day to day due to clear sky or overcast. While this obviously has very little impact in nature, it is a different story in an artificial aquarium. Plants in the wild seldom have the lush appearance of what most expect in the aquarium, which is achieved by regulating the light intensity/duration and nutrient availability. As soon as one starts fussing with this, the plants tend to show the effects, depending.

Algae can be more bothersome. I tried a no-light tank, a 10g in front of a window, and algae on the back glass was fairly extensive, and a small bit of cyanobacteria appeared. The plants in the tank grow toward the back wall, as all plants will grow towards the strongest light source, and this gave an odd appearance to the tank. On the whole, after one year, I moved the tank away from the window, added an overhead light, and a sponge filter (no filter was another aspect of this experimental tank, which housed 12 pygmy cories and 12 Boraras brigittae, and Malaysian Livebearing snails).

 

[shrimp_lass]

Yes, I would definitely consider trying to grow plants without light to be an experiement. So far my vallisneria is not doing well and I'm planning to take it out. I might actually take all the plants out of that tank and put them in the 55. The 40 is very tall, and I worry that my short plants aren't getting much light even with the artificial on all day.

The other tank, the 55, is in a spot to get a lot of good natural light if I keep drapes open. But I worry that the temperature will get too high during the day because it is a southern-facing window. It isn't in front of the window, but underneath it. No animals in it yet so maybe I will keep an eye on the temperature for a bit and see how it goes.

Sponge filters.... I've never used them but someone told me they will not do well in something as small as a 5 gallon. Do you agree?

That 10 gallon sounds awesome. What are your current tanks like?