"Fluid in his ears" is a little vague... What kind of fluid? Where is it coming from? Where in the ear canal is it sitting?
I assume your veterinarian performed a complete physical examination, including an otoscopic examination where he used an istrument to look deep in each ear canal, down to the eardrums. Any fluid in the ears are typically in this canal. The examination will determine if the eardrum is intact and if there are any other changes to the ear canal itself. A sample of the ear fluid or discharge can then be obtained and examined under a microscope. This will determine if there are any infectious organisms in the ear canal. Sometimes a sample may need to be sent to an outside laboratory for further testing (i.e., culture and sensitivity). Based on all this information, treatment can be recommended and started.
Ear cleaning is meant to help get rid of excess discharge and water in the ears. Most good cleaners are not water based, and will evaporate more quickly than water. This will help the ears "dry out." But it is important to use the correct ear cleaner at the correct intervals. Ears should ALWAYS be cleaned out after swimming or bathing to prevent an ear infection. Another alternative is to use a product called Swimmers Ear Astringent -also used to dry out an ear after swimming/bathing.
I have cut/pasted below instructions I give to my clients regarding proper cleaning and medicating of ears:
Proper ear cleaning
Good technique makes cleaning your pets’ ears easier, safer and more effective. Start off with a good cleaning product. Our cleaner of choice at Levittown Animal Hospital is EpiOtic Advanced, although some situations will call for a different product. Most ear cleaners, including EpiOtic, need to be shaken well before using.
One ear at a time, lift up the pinna (ear flap), and fill the ear canal with cleaning solution. It will flood out and make a mess, so try to do this in the bathroom or outdoors. Massage the base of the ear to break up any sticky or chunky debris in the middle ear canal. Then let your pet do the real work by shaking everything out. You can then use a cotton ball to wipe away whatever comes up from the ear canal. You may use a Q-tip in the visible external folds and crevasses –just don’t dig blindly into the ear canal or you run the risk of packing the discharge deeper down in the canal. Similarly, don’t push a rolled-up tissue or gauze sponge blindly down the ear canal.
Proper ear medicating
Selection of the most appropriate ear medication is based on microscopic examination of the ear discharge and sometimes a culture. Most ear medications come as a thick greasy ointment. They’re messy and don’t flow very easily down the ear canal on their own. Most chronic unresponsive ear infections in our experience are due to improper medicating of the ear canals.
Carefully follow the labeled instructions with regards XXXXX XXXXX the medication (if needed), keeping it refrigerated (if needed), and using it once vs. twice a day. Most ear ointment bottles will come with some sort of applicator tip to assist you in directing the medication directly into the ear canal. Remember, you will be treating the deep parts of the ear canal that you cannot see –not the external folds of the pinna! After squeezing the right amount of medication into the affected canal(s), you’ll then need to massage the base of the ear so that the medication can coat the entire ear canal all the way down to the eardrum. You should feel and/or hear the medication squish around as you massage.
While the medication’s label may instruct you to massage 2 or 6 or 8 drops into one or both of the ear canals, consider that the minimum amount. Normally, it will be difficult or impossible to count the drops as they come out of the bottle or tube. Luckily, it is alright in most situations to apply 10 or 12 or 100 drops into each ear without causing any harm to your pet. It is not okay, however, to put only 1 or 2 small drops into a big dog’s ear canal, as that will never be enough to coat the entire canal and get to the root of the infection. You’ll then end up medicating for many more weeks. So when in doubt, just put in more medication. If you need to clean and medicate the ears at the same time, clean first, then wait about 30 minutes to apply the medication. Continue to medicate the ear(s) until your next follow up visit, unless otherwise instructed. That way we can differentiate between an infection that has not responded to treatment vs. an infection that has responded, but then come back.