Minimum Number Of Individuals And Replacement

mangoed

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In the year I’ve been keeping fish, quite a few have died, primarily from causes which have been difficult to determine. However, apart from a disastrous experience with Threadfin Rainbow fish (where all four specimens snuffed it), the losses have generally been single individuals from a group. This has left me with various groups which no longer meet the suggest minimums for the type of fish.

For instance, the first fish I bought were 4 Harlequin Rasbora. A quick look at a couple of websites suggests that, at minimum, 5/6 individuals should be kept (though the actual numbers aren’t important to my question). In any case, one recently died and so I now have just 3. I would like to buy 2/3 more so that I comply with the suggested minimums.

Now, although sold as such, I don’t believe these fish to necessarily be Trigonostigma heteromorpha (they are probably espei or hengeli).

Basically, my question is, does this matter? Can I mix the 3 species? More generally, when maintaining a group of fish, especially given that occasional replacement appears to be required, how close does the species match have to be?

If the match has to been exact, then I can envision two problems... (1) I can’t tell exactly which species I have, so how would I know which to buy? (2) Even if I can identify my fish, what the LFS sells me probably won’t be the same anyway (since it was their descriptions that were inaccurate in the first place).

I should point out that it is not just the rasboras, I have 3 fish sold as “red-nose(d) tetras” which may be Hemigrammus bleheri, Hemigrammus rhodostomus or Petitella georgiae.

My two Corydorus sterbai look a lot like reticulatus to me and I also have 3 fish sold as Sparkling Gouramis (Trichopsis pumila) one of which, after some growth, turns out to be a Croaking Gourami. As for my Otos, I have no real idea (probably Macrotocinclus affinis).

Does it matter or how much does it matter?

-dan
 
In the year I’ve been keeping fish, quite a few have died, primarily from causes which have been difficult to determine. However, apart from a disastrous experience with Threadfin Rainbow fish (where all four specimens snuffed it), the losses have generally been single individuals from a group. This has left me with various groups which no longer meet the suggest minimums for the type of fish.

For instance, the first fish I bought were 4 Harlequin Rasbora. A quick look at a couple of websites suggests that, at minimum, 5/6 individuals should be kept (though the actual numbers aren’t important to my question). In any case, one recently died and so I now have just 3. I would like to buy 2/3 more so that I comply with the suggested minimums.

Now, although sold as such, I don’t believe these fish to necessarily be Trigonostigma heteromorpha (they are probably espei or hengeli).

Basically, my question is, does this matter? Can I mix the 3 species? More generally, when maintaining a group of fish, especially given that occasional replacement appears to be required, how close does the species match have to be?

If the match has to been exact, then I can envision two problems... (1) I can’t tell exactly which species I have, so how would I know which to buy? (2) Even if I can identify my fish, what the LFS sells me probably won’t be the same anyway (since it was their descriptions that were inaccurate in the first place).

I should point out that it is not just the rasboras, I have 3 fish sold as “red-nose(d) tetras” which may be Hemigrammus bleheri, Hemigrammus rhodostomus or Petitella georgiae.

My two Corydorus sterbai look a lot like reticulatus to me and I also have 3 fish sold as Sparkling Gouramis (Trichopsis pumila) one of which, after some growth, turns out to be a Croaking Gourami. As for my Otos, I have no real idea (probably Macrotocinclus affinis).

Does it matter or how much does it matter?

-dan



well what size is you tank and dimensions?
 
151L (about 40 USG). 92x55x30/41cm (the last dimension is minimum/maximum since the tank is bow-fronted). The volume I've given is the actual usable capacity.

Why?

-dan
 
Basically, my question is, does this matter? Can I mix the 3 species? More generally, when maintaining a group of fish, especially given that occasional replacement appears to be required, how close does the species match have to be?

I don't think it matters with Harlequins

I should point out that it is not just the rasboras, I have 3 fish sold as “red-nose(d) tetras” which may be Hemigrammus bleheri, Hemigrammus rhodostomus or Petitella georgiae.

I have "Rummy Nose Tetra's" aswell, and I got 5 from one shop, two of which died. So i went and bought some more from a different shop and they don't shoal together, I think because they are of different families. You can see they are because of their markings, some have extended middle lines in their tails, and some have red past their eyes.

Does it matter or how much does it matter?

It doesn't matter too much.. People are always saying "put them in groups" but I have had a solo or pair of fish which "require a group" which are just as happy. Although some fish are shoaling fish which do prefer groups..
 
So, basically, it is perhaps more important for some species than others. Your tetras are clearly different species so, to go by the 'rules', form two distinct groups of less than the recommended number. My 3 rasboras look happy enough to me but then they might be so much happier with two more identical tank-mates. My 3 tetras, however, do not appear particularly content - they've lost a lot of colour since I moved house and tank 10 weeks ago. I had hoped that, with time, they would settle in.

About a year ago I bought 3 marbled hatchetfish (though I've since noticed that 5 are the suggested minimum). One died almost immediately (was already ailing by the time I got back from the fish shop), then another practically took its own life this week by jumping out of the water into a miniscule gap behind the reflector. Unfortunately, it was baked when I found it. The single remaining hatchet doesn't look particularly bothered about being on its own though.

-dan
 

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