Its a guppy in the background, the owners need to be aware of a few things;
1)If they have a female guppy in the tank, they can expect babies, almost without a doubt.
2)The Kissing Gourami needs a minimum tank size of approximately 30 gallons, they can get anywhere from 6" to a foot long. If they do keep it in the current tank they'll will only be adding to its problems, there is a process known as stunting, the science of which i'm not too sure on but basically the fish will in no way be able to reach its full size in this tank which will negatively affect its health along with the issues that may result from the tattoo.
I would assume (correct me if i'm wrong) that your friends have jumped into fish keeping with little research and the common response (as i gave when i began fish-keeping) may be along the lines of, they will provide the best conditions possible within the realms of their financial capability and free time.
They may also keep the fish (as is) due to their daughter.
Personally unless they can provide a much larger tank fairly soon, in my opinion it would be cruel for them to keep it in its present conditions.
Its is likely to have a short life-span and if they don't want their daughter to have to go through the early loss of the fish (this comment may seem like emotional manipulation to a degree, it probably does have that element to it to be honest, but it is also the truth) they need to get a larger tank A.S.A.P. or re-home it with someone who can provide the suitable conditions.
3) If the tank is, as i am assuming, fairly new then they need to get educating themselves quickly. In new tanks a nitrogen cycle has to be set in place, via which toxins resulting from bodily waste and decomposed food are broken down. Without serious maintenance at the moment there is every chance all fish will be poisoned or again negatively affected and their health comprimised.
Please confirm if it is a new tank and i can explain or link you to a topic that does, which hopefully you can print off for your friends so they can get started on looking after their fish as best they can. Have they got access to the internet? I'd highly recommend they join up as i'd think it is unfair to expect you to be a 'go between'.
GB.