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Harlequin Rasboras Are Dying?!

13K views 6 replies 3 participants last post by  JKfish 
#1 ·
I got 6 harlequins from Petsmart a week ago. They're in a 10 gallon tank heated to 80* farenheit. They live with a betta fish and 2 ghost shrimps. They've been fine, up until the past two days. Now, they're dying! Both my males are dead, and the four females are looking alright, but a bit insecure. The two males didn't appear sick, or unhealthy, and my betta didn't really bother them. My harlequins are eating Topfin betta bits and they ignore the tropical fish flakes I toss in for them, so my betta ends up eating the flakes. I offer them blanched cucumbers and occasionally lettuce, but they ignore that too. Do you know what am I doing wrong, and why are they dying?
 
#3 ·
My tank is cycled, ammonia is 0, nitrites 0, nitrates 5-10. Ph is 6.6 to 6.8, a bit on the acidic side. It finished cycling probably 2 weeks ago, but I set it up to begin cycling about a month ago.

Also, when I said they aren't eating their tropical fish flakes, I meant that they are eating a bit, but not as much as they should. They seem to enjoy the betta bits the most.
 
#4 ·
From your information nothing stands out with respect to the water, so I'm thinking it is one of two issues. First, a 10g is small for a group of rasbora that attain close to 2 inches. In our profile of the Harlequin Rasbora it mentions 24-inch tank as minimum for a group of six. The other thing that bothers me is the betta; is this a male (presumably)? While you may not have seen evidence, the betta may well be intimidating the rasbora, which would explain your comment they look insecure. The presence of a fish which is tempermental and directly aggressive by nature will often intimidate subordinate fish like rasbora, which are one of the most peaceful group of fishes. Fish release pheromones into the water, and some other fish can pick up on these. And in the confines of a 10g they feel even more threatened, and have no where to hide as they would in a larger tank.

Byron.
 
#5 ·
my tank does have hiding spots; the right side of the tank has a large patch of silk ivy for them and the shrimp to hide in, where my betta (yes, he is male) doesn't usually go. There's also a driftwood ornament on the left back corner where they can hang around as well.

Before my two males died, the group wasn't insecure at all, they didn't really feel the need to tightly school, rather, they'd feel free to spread out around the whole aquarium.

*Sigh* I read they'd be fine in a 10 gallon tank, but I guess it depends. One of my males had a warped tail, which might have been why he died, and maybe the other death was just a freak accident? .... Wishful thinking :p

Anyways, because it hasn't been 14 days yet, I could still return my harlequins ... or get two more to replace the two I lost. I'm reluctant to return my fishies; I must admit, I've gotten attached to my harlequins, and I really wanted this small community tank to work out. If I do end up returning them, it'd just be one betta in a 10 gallon tank, unless I decided to divide it and put my other betta in on the other side. But, I don't want to be responsible for the death of more of my harlequins, and I want my fish to be in a healthy enviornment :p
 
#6 ·
my tank does have hiding spots; the right side of the tank has a large patch of silk ivy for them and the shrimp to hide in, where my betta (yes, he is male) doesn't usually go. There's also a driftwood ornament on the left back corner where they can hang around as well.

Before my two males died, the group wasn't insecure at all, they didn't really feel the need to tightly school, rather, they'd feel free to spread out around the whole aquarium.

*Sigh* I read they'd be fine in a 10 gallon tank, but I guess it depends. One of my males had a warped tail, which might have been why he died, and maybe the other death was just a freak accident? .... Wishful thinking :p

Anyways, because it hasn't been 14 days yet, I could still return my harlequins ... or get two more to replace the two I lost. I'm reluctant to return my fishies; I must admit, I've gotten attached to my harlequins, and I really wanted this small community tank to work out. If I do end up returning them, it'd just be one betta in a 10 gallon tank, unless I decided to divide it and put my other betta in on the other side. But, I don't want to be responsible for the death of more of my harlequins, and I want my fish to be in a healthy enviornment :p
I'd like you to be happy with your aquarium, but I can't tell you what to do as that must be your decision. I can only do my best to provide info on the fish and make suggestions.

Have you thought of returning the betta? There is debate over what I will say next, and other members here I'm sure will disagree, but in my view a betta [and I am assuming this is the "standard" Betta splendens, Siamese Fighting Fish, and not one of the quite different Betta species] is not a community fish. It deserves a habitat of its own. Non-aggressive catfish like some corys make suitable companions, but otherwise I feel they should be on their own, or in a large enough tank a male with a harem of females. Females are different, if no male is present, they fit into some community setups.

It is always possible the harlequins are diseased, in which case returning them would be a good thing:). They are also lovely fish. Some time ago I had the Harlequin [Trigonostigma heteromorpha] and currently I have two of the four closely-related species, Trigonostigma espei and Trigonostigma hengeli, and I am inclined to think the latter is the most beautiful of this group. The fourth species, T. somphongsi, is rare in its habitat and almost never seen in the hobby. All are nice quiet fish, extremely peaceful, colourful...what more could one want in a community fish?

Byron.
 
#7 ·
Thank you :)

Oh no, I can't return my betta, he's technically my little brother's ( I'm "just taking care of him"), and I've had him for 5 months now. In fact, the main reason why I have the 10 gallon tank set up, is for him. I also wanted a community tank, so thought, "hey, there's some fish that'll get along with him, and will make the tank look so much more beautiful and active, why not?"

The 4 girls look healthy, and aren't insecure and tightly schooling anymore... If they're sick, I guess I'll find out within the next few days, and if not, then it could be a freak accident, or the betta being there.

I've got some thinking to do to try and make the best decision. I think I'll let the tank be for another few days, and seeing how the harlequins continue to act, before making any more decisions. But, whatever I decide make will probably be dependent on wether or not my parents will take me to Petsmart again soon.

thanks again for your advise and help :)
 
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