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Discussion Starter #1
hello every one

im a aqua keeper at a pet supply store in auz.

i have a 40L tank and have 4 serpae tetra in my tank one of them seems to be a bully to the others and all the ones that i keep at the store have no problems with each other or any of the other fish i put in there.

am i having this problem couse it is completely new tank and they are deciding who is boss or do i have a fin nipper here couse was fine when was at the store.

im also gona put a black ghost knife fish in there eventuly and im well aware that he will most likely kill them when he is big but what are his chances of staying safe from the tetra when small ?

thank you for help

Velgore
 

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I kept serpaes years ago, and from what I remember, I had the same problem. Adding more serpaes seemed to help even out their behavior a bit. They shoaled after a few days of being together. As for the smaller fish, I would give it plenty of cover, but dont bet on it surviving. Serpaes can be viscious.
 

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Hello and Welcome!

Serpae Tetra are well known for fin nipping, the more of them and the larger the space the more this can be lowered, but they should never, ever be kept with long fined fish. Minimum shoal size should be 8 to reduce agression. Minimum tank size is a 20g long (75 liter).

A 40 liter tank is a 10 gallon, and is not large enough even for a juvenile BGK. Minimum tank size for these guys is 6 ft by 2 ft which is 180 gallons (681 liters). Even when 'growing out' these guys would need a larger tank. The tank must be, at a minimum, three times longer than their length and wider than their length. Their bodies are not flexible, so they need the width to turn around. Max size is 20 inches (51 cm).
 

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Welcome to the forum

Sounds like typical behavior. I kept mine with tiger barbs . The problem is exacerbated in a small tank such as that. Speaking of which, a 40 liter tank is too small for a black ghost knife.
 

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I agree with what all the other members have said. See if they'll give you a nice big employee discount on a big tank ;-) Has anyone else ever heard of red minor tetras ? I had them years ago. They closely resemble red serpae tetras but, they're not nearly as nippy. More like bleeding hearts in their behavior. A good substitute if you're a big fan of that shape and color of fish.
 

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Discussion Starter #6
i see what you guys are saying.
i has planned on getting a bigger tank but when the bgk had grown a little. they are my fav. would keeping it in a small tank till its grown be allright and if so how long will it take to grow?
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i see what you guys are saying.
i has planned on getting a bigger tank but when the bgk had grown a little. they are my fav. would keeping it in a small tank till its grown be allright and if so how long will it take to grow?
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Not really.

As mentioned, they must always be in a tank at least 3 times their length, and the tank must be wider then they are long because they can not bend their body much to make a turn.

Fish grow very quickly, you would have to obtain the full 6ft (183 cm) x 2ft (61 cm) tank within 1 year, possibly 2.

Since these fish are not at all rare in the hobby, I would strongly suggest not buying one until you already have the tank. They're not going anywhere, so it can wait until you have the means to care for them. Life happens, and it would be a real shame for you to buy the fish then any number of things happening in the meantime preventing you from upgrading to the larger tank it needs. Finding a new home for a fish that requires such a large aquarium is not something easily done and most often the fish suffers for it.
 

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Knife fish can turn on a dime, curling their bodies into a U shape. They are very fluid and maneuverable. That's not to say that they should be kept in a smaller tank because of that. The problem with keeping a fish in a tank till its grown is that by they time the fish has "out grown" the tank, it's WAY past due for the larger tank.
 

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Oh I didn't even notice it was 40l. Yea that's small.... I had my serpaes in a 29g and that even got crowded with the addition of other fish. Another thing, although basic, is make sure to switch up the decor in the tank, and switch where you feed them from regularly. This will help ensure that they don't get territorial.
 

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Discussion Starter #10
thanx every one. i may have to change fish then? i want a cool couler range and i thought the tetra red looked good. any ideas of fish that can go with them?
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There is some mis-information in this thread that I'll correct as I go. First off, Velgore, welcome to Tropical Fish Keeping forum.:-D

First on the "red" tetra, the species is Hyphessobrycon eques. Common names vary depending upon store, location, aquarists... as with all common names, they are next to useless. Serpae Tetra is the most "common" of these so I used it in the profile [click on the shaded name for the profile], but Red Minor, Jewel Tetra, Blood characin, Blood tetra, Callistus tetra are others one finds. The scientific names have changed too, as is explained in the profile.

The profile also notes that the temperament of this fish is variable, and the reason is explained there. One thing is certain: this fish is feisty, and prone to fin nip. You almost always see jagged dorsal and caudal fins. Keeping the fish in larger groups of no less than 8 but 12 or more is preferable, and in tanks no less than 30g (with no other fish, larger if other fish are included) can keep the nipping confined. But this is not guaranteed.

Another absolute is that this fish must never be combined in a tank with sedate or long-finned fish; the temptation is simply too great. And before anyone says there fish didn't... just remember we are talking normal behaviours of a species. The majority of fish in this species will behave according to the above, so the risk is there with the species.

So combining with something as quiet and sedate as a knifefish is out completely. I won't go into the specific requirements to maintain this beautiful fish, but refer you to the profile: Black Ghost Knifefish. It has very specific needs in terms of tank aquascape, lighting, and other fish. And it needs a very large tank while growing. It is inflexible, and this is part of its electrical field mechanism. More in the profile.

Byron.
 

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It was many, many years ago when I purchased the Red Minor Tetra. They were in a tank next to Red Serpae Tetra. I remembered that there was a difference in appearance but, I couldn't remember what the difference was. Reading the profile reminded me. The Red Minors didn't have the dark shoulder patch. Back then, that would have indicated that they were commercially raised rather than wild-caught. The kindly old gentleman at the fish store told me that they weren't as "mean" as Red Serpae. That seemed to hold true. The difference between wild-caught and commercially raised perhaps ?
 

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It was many, many years ago when I purchased the Red Minor Tetra. They were in a tank next to Red Serpae Tetra. I remembered that there was a difference in appearance but, I couldn't remember what the difference was. Reading the profile reminded me. The Red Minors didn't have the dark shoulder patch. Back then, that would have indicated that they were commercially raised rather than wild-caught. The kindly old gentleman at the fish store told me that they weren't as "mean" as Red Serpae. That seemed to hold true. The difference between wild-caught and commercially raised perhaps ?
This is a possibility, wild caught fish sometimes behave differently from tank raised. But in this case it is more likely the possibility of there being more than one species, as Weitzman suggested.
 

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This is a possibility, wild caught fish sometimes behave differently from tank raised. But in this case it is more likely the possibility of there being more than one species, as Weitzman suggested.
So are we saying that serpea and minors are one and the same and what I had was most likely a different species ? See what you mean about common names. I certainly do not want to mislead anyone. Guess I need to read more and type less.
 

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So are we saying that serpea and minors are one and the same and what I had was most likely a different species ? See what you mean about common names. I certainly do not want to mislead anyone. Guess I need to read more and type less.
I can't make definitive statements about Red Minor and Serpae being the same species because i don't know the species to which these common names may have been applied. But i can say that most of the time, the fish offered as Serpae Tetra and Red Minor Tetra are in fact the same species, Hyphessobrycon eques. But I can't emphasize too much that the common name is never a guarantee of accurate identification.

Second, it is possible that there is more than one species within the species H. eques, as Weitzman mentioned. This species is distributed over an immense area in South America, and as we know from other species, this frequently results in the evolution of distinct species. If it does not go this far (to distinct species), there is the possibility of there being variants of the same species. There are several instances of this among the characins in SA. Carnegiella marthae (the Black Winged Hatchetfish), Nannostomus marginatus (the Dwarf Pencilfish), Nannostomus beckfordi (the Golden Pencilfish), and Paracheirodon axelrodi (the cardinal tetra) to name some that occur to me.

Taking the latter, there are two very distinct forms. Throughout the Amazon basin, primarily the Rio Negro basin [an area the size of the country of France to give this some perspective] and up into the Peruvian Amazon, the form of P. axelrodi is distinctly differently from that form of the species that occurs in the Orinoco basin in Colombia. You can read how these vary in appearance in our profile. Gery suggested back in the 1990's that this might represent two distinct species, or it may simply be colour/pattern variants due to the two forms having evolved isolated from each other. The most recent scientific work suggests the latter to be the case. So here we have one species that has evolved into two distinct forms.

There is further info on this in our profile of each of the above-mentioned species if you're interested in just how they vary.

Byron.
 
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