Jenynsia Onca Biotope tank build

As some of you know, I've been a bit enamored with this unusual livebearer species since I discovered them about a month and a half ago on Aquabid. Well, I bit the bullet and bought an unsexed group. Now, since they are so new to the hobby, not a lot of info is available on them. There are some who still think that they are one-handed fish - folks think that for breeding, the males can only use their gono on one side and the females can only accept the gono on one side. This is not true, and is probably due to them being slow breeders compared to most livebearing fish.

Well, I've been doing a lot of research on them. They are coming next week and I want to have a great tank home set up for them, so I was looking at a biotope tank. After a quick look on Fishbase, which I trust as a fairly reasonable, scientific source regarding fish habitats, I have decided to construct a Lower Rio UruguaI habitat.

I will be using a 15 gallon Clear for Life tank with a solid deep blue backdrop (the fish are white, so a dark backdrop is a must). A bit of research has yielded two plants I'll be including - broad leaf sagittaria and echinodorus uruguaiensis (uruguay sword). I'll be looking for more plants native to the area (if you know of any with reasonable evidence that they occur in the lower rio uruguay, I'd be very interested to know about it). The tank will receive mostly natural light, but I may add a small light fixture if I find the plants need it.

I'm currently researching fish collecting expeditions in the area to see if I can find any references to specific plants that they noticed, and found in this research that corydoras hastatus and otocinclus cats are VERY common in the densely vegetated areas of the streams, lakes, and the rio uruguay itself, and will very possibly include some of these fish in the tank once I select a trio of the staple fish. Probably either a trio of Otos, or a shoal of 7-8 cories.

The substrate for the tank will be Azoo's plant substrate. I'll be adding a heavy leaf litter and some driftwood and mosses (assuming I can verify the presence of fissidens sp. in the lower uruguay - if not I will probably open up a few marimo balls and attach them to the wood instead).

I am still in the research phase as far as planting and tank setup, and finding info isn't easy, but I figured I should start the thread and get the ball rolling with you good folks.

 

I would love to see pictures when they arrive.

 

Oh trust me, pictures will happen. I'll be taking some of the tank, too, once it settles. Hopefully the dang tank arrives before the fish do... >.> sloooooow shipping from the Clear for Life factory. Srsly.

 

Well everyone, the fish shipped out today. They should arrive by Thursday (I hope). Fortunately, the tank arrived! So I went ahead and got it started. I added the substrate, which is Azoo Plant Grower Bed. I'm going to collect some oak leaves from outside my apartment and add them tomorrow (I had no patience for it today).

But I added a few inches of water and the wood I was planning to use. Let me just tell you, getting the wood in was interesting. I was wearing gloves which are too big, because I didn't want to risk contaminating the tank with the icky stuff I was dealing with from euthanizing a group of myco infected guppies. And the "lid" to the Clear for Life tank isn't so much a handy lid as it is a solid piece of acrylic bonded to the rest of the tank, with a filter/heater cord hole in the back and a light hole in the middle. So yeah, that was interesting lol.

I'm going to pick up a few plants tomorrow, and add them, and will continue planting the tank as I research and more plants are ordered in. I'm only going with tissue cultured plants if I can, as I know very little about these fish (no one knows about them) and can't say how hardy or disease-resistant they might be.

Anyway, here's most of the hardscape. I'm considering if I want to put any rocks in there, but I kind of like it with just the wood. If I add rocks, they will probably be river rocks, very smooth, but I dunno. I'd love to hear thoughts on it.





How is the wood placement? One piece is kind of sticking out the back of the tank, but I may leave it. I'm considering adding an amazon sword and letting it grow up and out the back of the tank (since there's a giant hole in the back), so that might work to my advantage.

 

That's a lovely piece of wood or is it two? I can't tell from the pic.
Interesting project, look forward to seeing its progression

 

It's two. One twisty oak(?) piece and a manzanita burl I collected a few weeks ago. Possibly the twisty piece is a manzanita root... I don't remember exactly where I found it so it could be either. Either way it's a nice hunk of wood lol.

 

I really like the look so far, JB! From your description I am seeing a gorgeous tank when complete!

 

Thanks shayla! I'm just hoping I can find all the plants lol. There's so littleout there on ccollection biotopes for these fish that my options are limited. Best I can guess, it will be amazon-like with some Uruguayan plants as well.

 

The fish arrived today They look great! I have one girl and it looks like 4 boys, but we'll see in more detail once I get them comfy in the tank. Looking at the size, I'm reeeeally glad I went with a 15 gallon instead of a 10. The females are pretty big if this girl is anything to judge by.

I added two medium sized amazon swords and a small row of moneywort to the tank. The rest of the plants are still in transit, so hold on, little fishies.

 

Pictures, pictures, pictures !!

 

What is the name of the fish

 

Their scientific name is the thread title...
Rivieraneo I will get pics ASAP. Gotta light their tank lol.

 

The fish sound really cool! Can't wait for pictures!

 

I got some pictures! All but the largest male are fairly skittish. He's bold as heck and hanging out near the front of the tank.

There doesn't seem to be much size difference between him and the female. I don't know if that means she's young, or if they just don't run quite like some other livebearers where the girls are huge and the boys tiny. As it is, they are not striking fish, but they are a nice silvery white color with black dots, and I really like them. I'll have to update as I watch them over the next few weeks. Since I ended up with only one female, it'll be interesting to see how the males act in the tank together.

I am so impatient to finish the tank! I want the plants, the filter (which did not arrive on time, unfortunately) and the c. hasbrosus RIGHT NOW! lol!

Anyway, without further ado, here is the new Jenynsia Onca breeding colony:







The largest male:

 

Looks like they're settling in well, I can't wait for you to get the habrosus too they're such cute little corys

 

They are all out and about this morning, which is a great sign. Seems they're not quite as shy as I thought. I'm sure they will come out a lot more when I get the plants in and the filter running. Good thing they're from slow moving streams or they'd be sad fish right about now lol.

I'm going to be letting the pH lower in the water until it sits around 6.5-6.7, to mimic the only info I can find on their natural habitat.

Also it's C. Hastatus, not hasbrosus, sorry.

 

Update: The poor fish are kinda stressed. For reasons unknown to me, their filter STILL hasn't arrived, and I don't want to risk contaminating their tank with one of my other filters (for those of you who don't know, I have a mycobacterium issue going on in several of my tanks right now - don't want to transmit that to these new little guys).

However, their colors are coming in nicely. I'm still trying to figure out how the light fixture they sent with the tank works... it's basically a black box with no electrical to it, no bulbs.... just trying to figure out if I want to buy the rest of the pieces to put it together or let it be a natural light tank and figure out alternative photo lighting. Anyway at least two of the fish have colored up. Their black spots have deepened in color and the lighter colors are heading more towards white.

According to the UPS website their filter is arriving today, so hopefully that will relieve some of the stress and get these guys the oxygen they need.

I will take more photos when the weather gets better (I'll have actual light that way), and see how they begin to look after they get some aeration in their water.

 

Woo! The filter arrived last night, and the fish are MUCH happier. They retreated to the bottom of the tank, into the many hiding places I made for them. I fed them some shrimp this morning, and they don't seem to like it at all lol. Wondering if a veggie flake would be more appropriate. They ate it and spit it out... thank goodness I got some plants in the tank to soak up some of that funk. Since the shrimp was pretty much powdered by the time they were done with it, I have no way to remove it.

I need to upgrade to a 5-10 gal. air pump to get more flow, because once I finish planting this tank, it'll be pretty lush in there.

Here's what it looks like as of now. I added some plants - echinodorus "rose", Echinodorus "red flame", echinodorus urguayensis, in addition to the moneywort and amazon sword that were already in the tank. I've ordered some pennywort as a floating plant, and some pygmy chainsword to use as foreground unless I can find a more appropriate plant. I also want to add a stem forest on the left side of the tank, and possibly twine the pennywort around the driftwood.








My next step will be to collect some oak leaves from my yard, rinse them and add them in. They will make a nice leaf litter. When I do this, I'll need to buffer the water pretty heavily to keep the pH where I want it (for this species, appropriate pH seems to be from 6.5-7.2, though they can likely tolerate more alkaline water if needed).

Interestingly, the fish are significantly shier than I thought they would be. They hide in the wood's caves unless I startle them out. I've also observed and interesting behavior. I thought it was just them being weird in a new environment, but it's becoming apparent that it's something else. Perhaps a breeding behavior? I don't know. But occasionally, the fish will ram each other. There doesn't seem to be any malice in it, they just randomly run into each other and one will kind of bounce off the side of the other.

I'll continue to update as I observe their behavior, especially if and when I add catfish to the tank.

 

Coming along really well!

 

Thanks! I can't wait for the water to clear up so I can actually see the tank, lol. It's a bit gooey from being filterless for the whole weekend

 

Oh well, a minor setback only

 

There has been a slight revision to the stocking plan for this tank. I'm on the hunt for Hisonotus Aky, a bright green, oto-like loricarid which eats primarily algae. Since this tank is directly under my kitchen window and that's it's light source, I expect I'll see at least green algae and brown diatoms, if not something else as well. I'm hoping to locate a trio of the hisonotus to A) clean algae off the tank walls once the tank establishes and B) add some color to the tank.

I briefly considered adding a pair of apisto borelliI (now common in the Rio Uruguai) to the tank, but that would throw off the aesthetics. I really want the Jenynsia Onca to be the main attraction. As such, if and when they breed, I'll be revising the group I keep and getting rid of some of the males. I'm hoping to end up with two adult males and three adult females as my breeding group.

I will be adding a mystery snail ASAP as a cleanup crew, and possibly, if I get brave and once the tank is very well established with lots of "gunk" around for it to eat, a spixI snail or two. I've found some information suggesting that both of these snails are VERY common throughout the amazon and uruguay basins and it's likely that any environment where Jenynsia Onca would be found would contain one or both species.

If anyone happens to come across Hisonotus Aky or a similar species for sale, it would be great if you'd let me know. If I truly can't find them, I'll break down and get otos, but I'd like the splash of color.

 

The Hisonotus Aky looks like a very cool fish! I hope you can find some.

 

I've contacted The Wet Spot regarding them and also joined PlanetCatfish in the hopes that some of the folks there who breed them are in the US and willing to sell. I also have TheBettaBar on the lookout for some, since she works at a giant tropical fish store lol.

 

Look forward to your getting some of these neat looking critters.

 

I love the drift wood!!!

 

Thanks, Christopher! I collected those pieces and a few more (turned my poor boyfriend into a pack mule LOL) with the hope I'd be able to use them in my South America tanks. They had exactly the look I was going for. I'm redoing one of my other tanks because I have to break it down due to disease, and the new tank will have the other bits I collected.

 

Latest pics. I added a few more plants, including hornwort and brazilian microsword. Moved the uruguay sword, but I owe the tank two more of those, as soon as I can find them (@jetajockey)

Fish are loving it so far, and I've been able to remain very true to what the biotope should look like. Hopefully the tank gets enough light to carpet the microsword. If not, I'll have to try another variety.

Anyway, enjoy

 

Joshua, from batfish aquatics, might have a lead on some hisonotus aky If he gets them, he'll be getting a hundred or so and will likely be willing to part with many of them. Hopefully he'll be able to sell me a trio when the SA exporter gets the fish for him!

 

Just a little video of what happens when I feed these fish.

 

cool video! That wood piece is very impressive, fits well with your biotope! Wish I could find some driftwood like that outside, lol.

 

Your tank looks lovely I do like natural looking tanks, good luck with your breeding project & keep the pics/videos coming

 

cool video! That wood piece is very impressive, fits well with your biotope! Wish I could find some driftwood like that outside, lol.

I live in the national forest and we have several big groves of Manzanita around. That's a burl I collected on the roadside, lol. It had that large root attached and when I ended up getting this tank, I knew exactly what to do with it. The second piece is just a root bit. You can actually get pieces like this from ebay and Manzanita Burlworks, but it takes some hunting. I lucked out when I came across that piece

My snails should be arriving today! Yippie! Then all I'm waiting for is for Batfish to get the hisonotus aky, so I can beg a trio off Joshua lol.

 

Looking really great! I think those fish really are quite pretty. The whole setup is perfect. I can't wait 'til you get the *green fish* too!

 

Guh. My least favorite part of these tanks is the plant melt phase LOL. Since I dump so many plants in at once, I always seem to get a dieoff. I think it's partly from changes in water chemistry and plants moving from emersed to submerged form (I buy a lot of tissue cultured plants). And partly from the plants getting used to the nutrient level provided by the fish, and the new light, etc.

Right now, the red melon sword in this tank is a pile of mush with two healthy leaves. It looks so pathetic... lol. Hopefully those mystery snails I got discover it soon and munch it down.

I'm too embarrassed to take pictures or video of it such a sad looking plant.

 

lol, it'll pull through. How low is your lighting?

 

100% natural daylight. So whatever that is on any given day. It gets direct light only in the mornings, and indirect sunlight all daylight hours.

I know it'll be fine, as I had a similar plant do the same thing in my wild betta tank that was 100% natural light, and it's actually one of the nicest swords I have right now. It's just really ugly in the tank.

In other news, I can't find my snails I'm hoping they didn't crawl completely out of the tank, as it does have an opening they could exit through... that would be lame.

Edit: Okay, all three of the snails that I looked for for two hours last night have magically reappeared in the tank. Weird.

Oh well, maybe they were getting bugged by the fish.

Oh and on that note, unlike many livebearers, these guys don't seem to be very nippy. They're funny little fish. I often see the female "ramming" the smallest male (who is totally in love with her) but never any biting.

 

The ramming behavior continues. I often see the female chasing the smaller males around, especially the smallest one. But again he's the one that bugs her the most.

In other news, the tank is going through the traditional daylight tank green algae bloom. Lovely green fuzz all over all the walls. I can't get those Hisonotus Aky soon enough... lol.

 

They are really lovely little fish. The spots are just fantastic!

 

I've finally gotten some more information on them! A friend in the Netherlands knows a bit about them and was good enough to share his knowledge with me. Apparently they ultimately prefer a small amount of salt in their water. Somewhere between fresh and brackish water. Their natural range includes mildly brackish environments along with straight freshwater.

I also got some information on breeding. As it turns out, they are quite picky about their mates and tend to pair off. Which means I need more females to increase the chances of mating pairs. Now I just have to figure out where to order 3 more sexed fish lol.

I am still debating whether I want to add any salt. If I'm able to find the catfish I want, salt wouldn't work at all as they are loricariids, scaleless, and they really dislike salt concentrations in their water. They would also be wild caught fish so a bit more sensitive to these things than captive bred.

There is algae all over their tank walls. It's hideous. I added liquid carbon to at least keep it so I can see into the tank, but I really can't wait for the algae bloom to be over already.

Also as a side note, it's thunderstorming right now and the fish are going absolutely insane LOL.