Crenuchus spilurus (Sailfin Tetra)

[igmillichip]

Soooo.....a thread on these fantastic fish.

Some people may wonder why on earth would I rave about these fish.....well, not even these videos can show you how interesting these mini Hoplia-look-alikes are.

Although these fish are shy, peaceful, can be difficult to feed, and require good water. they are great community fish (so long as other fish are not too boisterous or too small to easily fit in the Sailfin's mouth).

Not easy to get a video of these as the fish are kept in a clay/peat water....but by virtue of a new headlamp, I have some videos.

The first is just a nice Intro video.
The second is the bizarre way they attack flake food on the surface.





I'll do some more vids of them feeding in different styles.

It has been many years since I last bred these, so I am hoping to have a video of the cave-spawning (if I manage to tempt them to breed).

Maybe JoeMc will join in on this thread.

Ian

[bmcg]

They are great lookin and you really love them tetras Ian !!

[joemc]

Thanks for starting the thread Ian, otherwise I would have been sending pm's back and forth with questions on these great little fish. This way everyone gets to see and learn about the fish!
I got some of these fish recently,April the 29th, and a few more on May 4th, so my experience with them is very limited to watching them settle and feed.
Their stalking and feeding is very interesting to watch. They have been offered and have eaten Tetra prima (as it sinks ) Tetra crisps (from the surface and sinking) they have shown no interest in food once it hits the bottom of the tank so i have a couple of small whiptails in with them along with a herd of cherry shrimp to mop this up. Live food wise they pick off the cherry shrimp and are not afraid to have a go at an adult sized one, other live foods they are being fed are glass worms mosquito larvae large daphina, large cyclops and they have been tackling and eating the odd 3-4mm body sized water boatmen i have dropped in to them!
With the feeding they are fed 3-4-5 times a day and are filling out, putting on size and any knocks, scratches or split fins they would have had as a result of the catching shipping etc are starting to heal and disappear.
I posted a couple of pictures of them in the 'recent purchases ' thread (maybe a moderator could stick a copy of them into this post)
Looking at your setup Ian, mine is very similar to yours, water params, peat stained (lumps of turf in the tank!) sponge filtered etc, the only difference is I have some live plants in there too.

[igmillichip]

Cheers Joe for joining on this.

Mine will eat off any part of the tank....even off the floor (although, they do prefer the food where they want it....looking like something alive).

Only fake plants would last in my tank as I have no light in it........the light at the side is from my brine-shrimp hatchery.
In fact, I have no lid on the tank as I preparing the fish to spawn at some time in the future.
The lid will go on to increase air pressure above the water when needed, and when I start running the overhead filters at full rate (at present, the overhead powers filters are switched off).

I have presently a 4:3 male:female ratio; that will be cut to 1:3 male:female for breeding when the most dominant male shows his colours (yes, there will be a few nips fins along the way, but nothing to worry about).

So for a fish that is 3 to 4 euro a pop.....you can get a lot of fish for that money.

ian

[joemc]

the Ratio of my fish is 1:2 , a dozen specimens in total.
I have read a bit about the methods to stimulate the fish to spawn online, but as always a 'real' account is much better reading, so spill the beans Ian, you have had success with these before, and hopefully again!
My fish would have a bit to go before they would be in what i would consider breeding condition / size.... some of your fish on the other hand look like they are there or there abouts.
Keep us updated with the stages of the procedure to get their brain saying ''spawn / reproduce'' as you move along, or even a step by step guide would be great.
Another thing that has been bandied about re these fish is the belief that they have 'infrared perception', I think it was Heiko Bleher that mentioned that there was a study done in some institute or other in France (I think) a few years back, and that he had supplied the 1200 fish for the research... know anything about this Ian?

[igmillichip]

I posted a recipe on the other forum Joe on how I plan on 'tempting' these to breed based on previous experience.
(I'll copy n paste that here).

The sensory system of these fish has been known for a very long time. I was doing work on these and on Serrasalmids back in the 70s.
So, the notion of IR is not new.

It was suspected that the 'Notched Neck' (the "crenuchus", as that is what Crenuchus means) may hold some keys.

I noticed something on the video after filming that I may look into a bit more.....it seemed as though the pupil turned into a triangle in some shots.....but that may be a video artefact.

ian

[igmillichip]

Here is a copy-n-paste on what I posted on the other forum.
...............................

OK...so for how I used to get these to breed.....simulate their seasonal changes.

In this batch I bought 4:3 males:females, but that is to give me a 1:3 male:female ratio in the end.
3 of the males will be removed when one shows his dominance.

The water is kept in good condition (with a low conductivity, peaty, and soft) for a long period with very regular partial water changes, then there will be a period of letting the tank 'slip' a little:
water changes will be reduced, pH will rise slightly, conductivity will rise slightly, and the lid of the tank will be removed (making sure the fish can't leap out). Feeding will be reduced somewhat, and the filter speed will be turned down.

Have bogwood etc that will be ultimately out of the water and thus effectively reducing the width of the water as the water level lowers....simulates narrowing stream banks.

Now, this is slightly dangerous for a delicate fish such as these....so it needs to be done with care.
Having modern zeolite resins around (such as ammonia absorbing clays or JBLNitraEX is a good idea).

Then, do a largish water change......add in fresh water, and slowly reduce the pH and conductivity, add more peat and ammonia adsorbing clays (this will also increase the 'mulm' on the bottom of the tank....that is what you want).

Increase the flow of the filters, and have some water trickling in from above.

Add the lid, and increase the air pressure. Feed plenty of frozen food (bloodworm).

.....and keep the fingers crossed. These are not always a 100% guarantee to breed.

Now, they sometimes may spawn on the odd occasion in the tank anyway, but that is leaving things to chance a bit too much.

.............

ian

[Anthony]

Great to read the experts posts.
I am interested in this myself as I am starting a planted tank and I want to have a few unusual species
of fish in it.

[joemc]

what temp do you keep your fish at Ian? and is there a drop with the attempt to get them to spawn?

[igmillichip]

Good Question.

At present I have them at a high temp 29/30 C (and in with Chocolates). I find that that is good as it maintains a good immune system when moved.

For conditioning and breeding, I would have the temperature around 25 C.......ie no change in temp to stimulate breeding.

Maybe a few transient rises in temp during the pre-breeding may help stimulate a difficult pair.

Ian

[joemc]

tks, mine are in two groups, one at 25 and one at 26.5, that's why i asked, the group at the higher temp are eating more and are growing before my eyes, the biggest male has really come on and has really 'reddened' up and taken up a position in a cave. The females are filling out nicely, I think I will increase the temps a little over the next week or two, to date both groups are getting a daily water change of between 10 and 15 %

[igmillichip]

So are you going to try to see if they just spawn as in normal everyday tanks conditions? or are you going to attempt a 'season' change?

With 2 groups, you could try both.

As these fish are only 3 to 4 euro a pop, and not the most popular fish on the planet (I don't know why though), you'd never make a million from breeding......but I still believe attempting to breed these is important.

There is, afterall, more to reaching the summit of Mount Everest than getting a few bob in your pocket (or is that me just being a bloody hippy again?)

ian

[joemc]

I think i will leave the group in the tank that are at 25 degree as they are, maybe an increase of a degree but that's all as the tank has other fish and plants in it and just see how they do with a steady care, feeding, lighting and water change routine all regular, seeing if in time they spawn without any triggers as you suggested.
I will continue to feed the smaller tank heavily for now and that is the one i will try making changes to, working along the guidelines that you posted, I am not in a rush, I think the fish still have a bit more growing to do, so lots of food, little and often, and for the moment just gently increase the temp to 28-29 while keeping up the water changes.
oh, and they have started to eat from the floor, but it is definitively not their method of choice!

[joemc]

missed the last two paragraphs in your post.......... story of my life, i talk before the other person is finished... oh and i generally don't listen to what they were saying either i have been told
so re the making the million from breeding these, or any other fish, naw, born poor and will die poor, i would be delighted to see 6 or 12 offspring surviving to get to the stage where they could be passed on to someone else with an interest in them, the crack and enjoyment is in seeing them do their thing in their own special way, that's it really

[igmillichip]

That's the spirit.