Help! killer fish!!

Question
Hi Karen!
Ok, so i go out today to this huge market with many many different pet stores..i go into a fish shop and I buy 1 heater,1 mini filter/aerator, 1 red betta i named triton, 5 neon tetras and 3 guppies.I also bought a few goldfish for my goldfish tank as it was looking a little bare. I bought the guppies which had smaller tails and were'nt very colorful..they use these fish to feed larger fish there..oh and also bought 1 plant and i already had the gravel at home..so I put the tetras in first and they seem happy swimming around in their new home..next in go the guppies who also seemed content..the fish store guy said it was ok to put the fish in together but he told me not to put the shrimp in as they killed fish..he demonstrated with a dead fish and the shrimp tore it apart! so i did'nt buy any shrimp..i also did'nt buy any frogs or minnows as they were out of stock:(..ok so now for the betta..i did'nt put it at once, i just lowered the cup into the water to see if it would flare or attack and to give it a little time to adjust. He was fine, he didnt even flare! i specifically chose this betta because he was'nt even flaring at the other males in the cups next to him, he seemed so docile..so i let him in the bowl and he looked really happy..he was shy at first hiding in the plant but then he explored his territory and got along well with the other fish.so here i have this really gorgeous bowl and im looking at it and about half and hour later they were still getting along fine but somehow, i fell asleep(i kept it on my bedside table).i wake up about about an hour later to find my sister screaming at the top of her lungs! Triton ripped apart 2 of my 3 guppies and i cant find 1 tetra:(( i start freaking and i put Triton back in his little cup i bought him in. My filter/aerator wont work and i find the other tetra in it:( i have no idea how it got in..the slits in the aerator are too small for any fish to get through..so i clean up the mess , fix the filter(thats when i found the tetra:( )and i put the plant back in..the guppy and my 4 remaining tetras seem ok now..i just could'nt keep Triton in his cup so i have this vase which is roughly about a gallon, im not sure..with a little gravel..i don't know what to do!! do i need to get another bowl and filter for Triton? will the tetras and guppy be fine in the current bowl? do i need to get another guppy or two to keep my lonely guppy company? is Triton fine in his vase now? Im really depressed!!please help!
Thank you,
Gayantha.M

Answer
A big hello again! Wow, what an exciting story! :)

I'm sorry to hear Triton did that to those other fish... Fish are always unpredictable, you never know how things are going to turn out. While the bowl is OK for the neons and guppies and Triton the betta, the bowl's very small environment likely contributed to the unfortunate fish losses. If these fish were put together in a aquarium of even say 10gallons or more and ideally well-planted, you likely wouldn't have woken up to such a sad sight. In a aquarium with hiding places, pestered fish can get away from the aggressive ones and stay out of serious harm long enough for you to see what was happening and remove the aggressive betta or the bullied fish themselves.

Is there any way you could get at least an inexpensive 10gallon aquarium with a simple hang-on-back power filter and a heater for your remaining neons and guppy? They would be so much happier in a planted aquarium with several more of their own kind and they would make a splendid setup. The neons and guppy might do Ok in the bowl but they may not thrive. There could be water quality issues that would certainly kill the poor neons. Daily water changes would be best for now until you could get your neons and guppy in a better environment...
If you could setup a 10gal for the neons and guppy, then you could devote the bowl to Triton. Which is really all a bowl can really hold. Triton would love to have the bowl as his home, it's especially good that you have this bowl heated and filtered! Plenty of cheers for that!

Say if you did get the neons and guppy an inexpensive 10gal. You will want to not only have it filtered and heated but also be sure to get aquarium tests for ammonia, nitrite, and nitrate. It's essential to test your aquarium everyday for these levels until your aquarium cycles, or when the 'good' bacteria build up sufficient colonies to keep your ammonia and nitrite at ZERO.
If you need anymore help on this, let me know!
When your aquarium cycles, you can add a few more guppies and several more neons. Neons are happiest in a big group.

Triton will likely be fine in his vase for now. Just make sure his water doesn't get cold and don't forget to keep his water very clean. Changing 100% of his water everyday to every other day is ideal for bettas. Be careful when you change his water and use the cup he came in to gently scoop him into (this takes practice and patience) and set him aside somewhere safe, also put something over the open part of the cup so he wont jump out while your cleaning his vase. Make sure you have some replacement water ready for refilling, it should be dechlorinated with a good water conditioner and equal in temperature to the old water in his vase (if it's a few degrees higher that's fine) remember not to use any chemicals of any sort when cleaning the vase, jump dump the old water out (great to pour on outdoor plants) and make sure the gravel/marbles are well-rinsed in by stirring it around in the old water or use tap water to rinse the rocks. Try to work quickly so the little betta isn't stressed for too long.

I really hope this helps and don't feel too bad. These things happen and you never know how your betta's personality will be. I'm really astonished that Triton did what he did in fact! But I know aggression issues can be very common with many kinds of fish.
Karen~