• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

crystal red shrimp with pencilfish?

AlecF

Member
Joined
15 Sep 2021
Messages
569
Location
Edinburgh
I have some crystal red shrimp arriving soon. I suspect the peacock goby in my big tank would make a meal of them. I temporarily have Beckford's pencilfish in my smaller 60 litre tank. I'm hoping to get rid of the pencilfish very soon as the tank is too small – if anyone in central Scotland wants 3M and 1 F pencilfish free, just let me know, collection in Edinburgh, asap. The dominant male pencilfish chases the large amano in the tank all over the place, but I think that's a size issue, like sparring, in that crazy macho way of the Beckford. I won't have the pencils and red cherrys together long enough for the shrimp to breed, so shrimp lets are not an issue, but the cherry's will arrive small. Will the pencils ignore them or eat them? (As I'm here, if anyone in central Edinburgh wants some free Least Killifish I have babies and semi-mature you are welcome to, why not have the pencilfish and some Least Killifish? Advice welcome.
 
I think I mentioned in a post on another thread but it's a mixed experience for me. My pencils were fine for years with shrimp and the population of shrimp boomed but then after several years the shrimp population was decimated as the pencils turned on them. This was with beckfords but I've had more timid pencils actively hunt shrimp albeit not the adults.
If the shrimp are a half decent size then I think you will be ok temporarily unless your pencils are very nasty but I'd introduce the shrimp in the dark so the pencils don't see them as a food introduction.
 
Thanks so much, I'd have to say my pencils are nasty! Or the dominant male always is. They do seem to vary behaviour more than most fish as one sees reports of them being peaceful, but mine have been testosterone Visigoths since the second day they arrived. I think I will move all my fish around, transfer the killifish to my fry tank, and put the shrimps in with the fry in a Nano.
 
I didn't realise that Pencils were so aggressive. Have any of you experienced this with Dwarf Pencils too (Nannostomus Marginatus) - I've always fancied them when I get a bigger tank, but reading this is putting me off a little.
 
Hi all,
Have any of you experienced this with Dwarf Pencils too (Nannostomus marginatus)
Same issue, the males don't like one another and the females develop a pecking order. I kept them in a 60cm tank, which wasn't ideal, if I tried them again it would be in a much bigger tank. It wasn't the aggression that did for mine, some developed <"thyroid tumours">, and I didn't know how to <"treat them"> at the time. By the time I found out I didn't have (m)any males left.
I've always fancied them
They are <"fantastic fish in a planted tank"> they really sparkle and they aren't difficult to spawn, if you feed them a good diet (including mosquito larvae and /or fruit-flies (vestigial winged <"Drosophila melanogaster">).

cheers Darrel
 
Last edited:
Thanks Darrel, much appreciated. I'm a beginner, but it seems one of those cases where some people aver they are peaceful, as theirs are, but some of us have bad experiences. They are beautiful, but I'd only keep them species only. Mine even bothered my corys. I had been considering the dwarf pencils but will avoid them altogether as I can't do a species only and the aggression makes a tank stressful to watch. They are beautiful fish and I can see they work in some community tanks. Currently I still have 3 hiding behind an Almond Leaf and 1 hyper vigilant male patrolling the cube like a U-boat. What's amusing is that they have a truce for 5 minutes when the lights come on, but soon they remember their struggle and the war begins over again. Again, I just want to stress that my Beckford's went after peacock goby, Cory, and amano. That was in a well planted tank.
 
I don't think they are much more limiting than plenty of species of fish. People avoid tiger barbs, serpae tetras (or other fin nipping or bullish tetra) or dwarf cichlids because of their reputation but if you adjust the way you keep them then they can be very rewarding fish to keep, just not for every tank.

My thoughts are that it can just be the luck of the draw with pencils. I'll admit, and normally do, that I'm a fan of the family and that I perhaps keep them differently to most which could be why I've been alright with them. I think having a thickly planted tank where there are masses of breaks in lines of sight and individual territories is most important. The next thing is to get a big enough group and a dozen minimal with a female heavy ratio. I think this is when people are unlucky as with just a swish of the dealers net you could be in for a bad time.

Whilst mine have been peaceful to anything else ive kept them with I have found that males who constantly spar can develop bacterial infections due to this behaviour so can easily see how they could assert this aggression elsewhere.
 
Agreed. I tried to buy females but it didn't alter much and then I lost some to Melafix. My M divided the tank, which is 100 litres, well planted, but they were always invading one another's territory. The one thing I;d say is that a beginner can easily get the info on Tiger Barbs being nippy, but pencilfish are often sold as "peaceful" For them to be peaceful you have to be lucky, have the right kind of tank, have the right ratio, and you still may have issues. I never minded the shield barging, but there was a lot of chasing, and that's what spilt out to the other fish. I tried setting up a 60 litre cube for them and was going to get more F but in the end I realised it was just not a big enough tank, so they have to go. They do need a lot of space. I wouldn't have brought them if they hadn't of been advertised as peaceful. I don't think they'd describe themselves that way! They are beautiful fish though and must be very rewarding when they work. I wasn't a member here and this is such a valuable place to learn more and get some wise cautions.
 
but pencilfish are often sold as "peaceful"

I have to agree. Even Seriously Fish doesn’t make a big thing of the aggression, though does suggest a group in excess of 10. I didn’t realise they were that bad until I read this thread. If I ever get any marginatus, it will be in a large tank (150-180cm), and a group of 20-30 - though I’ll be thinking twice about doing it now.
 
Last edited:
it will be in a large tank (150-180cm), and a group of 20-30 - though I’ll be thinking twice about doing it now.
They’ll be fine in a tank that size. My mortenthaleri which are much larger and a lot more aggressive were just about ok in a 80cm tank and are fine in a 150cm where they have plenty of space to get away. They’re a fish that have a strict hierarchy but provided you have enough fish no fish should get singled out. I prefer them to other characins as they’re a lot more interesting and almost cichlid like in their behaviour.

Cheers
 
I don't say they are always that bad – it's as you say, a matter of luck, and the kind of care in terms of set-up that isn't for the novice. They'd make a lovely species only species. Mine did spawn easily, and I suspect they may try to leave behind some more fry when I get rid of them!
 
Perhaps I'm a little blinded on my opinion of the family, mostly due to what Conort2 has said perfectly above, but I haven't found them to be that aggressive at all and I've kept quite a few different timid species and sold plenty to all sort of community tanks (and I don't remember anyone having a problem, not that it doesn't mean they didn't). I do definitely see the potential for aggression but I guess it could just be down to perspective or tankmates how that turns out.
So from my personal experience or from my old lfs perspective I would have happily said they were peaceful (with a few species exceptions) but from reading online about others experience I'd now caveat that even if it goes against what I have personally witnessed. This is where forums help over just descriptions.
 
I did wonder whether having an uber lord type fish would intimidate them into behaving better. In my tank they were the same size as the goby's and intimidated them from day 1, even though there isn't much visual similarity. I didn't have the capacity to add any larger fish, but it could be an approach – I'm too much of a beginner to know. I do agree with you, these forums are such a help. The fact they even pecked and snipped at the corys was what really did it for me! It's interesting that when I first got them I thought the problem was one rogue male, and I returned him, but as soon as he was gone the next dominant male behaved the same way.
 
I think you have hit the nail on the head there Alec, with them being better with slightly bigger tankmates that can take a little aggression. I think beckfords make perfect dither fish for apistogramma because they can put up with a little aggression from the cichlids as well and mostly keep out of their way near the top anyway. I kept mine with a group of borelli for some years and it's one of the nicest, most harmonious, tanks I've had.
 
Yes, I think we've cracked it. That's good advice to share. I can imagine that if they weren't top of the pecking order they'd behave very differently.
 
Back
Top