There is a proper way to train dogs who are leash-aggressive, and the wrong methods (like dominance- or force-based methods) can backfire and lead to more aggression. That is why I would encouraged you to read out to a certified trainer for a consultation. You can location trainers in your area via the following websites:
AVSAB: https://avsab.org/resources/behavior-consultants-near-you/
IAABC: https://iaabc.org/consultants
CCPDT website: http://www.ccpdt.org/dog.../certified-dog-trainer-directory/
KPA CTP: https://www.karenpryoracademy.com/find-a-trainer
The trainer may be able to advise on the behavior at the dog park too, although I agree with the other posters that it would be best to take a break from the dog park until you have things sorted. Best of luck!
Jack Bogle gave this famous advice to investors: "Don't do something, just stand there!" The point being that sometimes it's best to just see how things play out before trying to fix something that may not need fixing.
Here is an excerpt from "The Culture Clash", which details the ways in which humans and dogs see things differently:
"In dog culture there are no letters to the editor, slanderous gossip and backstabbing, guilty feelings, democratic institutions, or lawyers. There are growls, snarls, snaps and bites. Aggressive behavior does not fracture relationships in dog society. It’s all taken very much in stride."
Given that he's generally fine, my advice would be to just see if he grows out of it. Dogs can really sound as if they are ready to kill, but teeth never meet flesh and it's really not a big deal. If it worries you stay away from situations -- like dog parks --where the aggression can get out of control. (I wouldn't go to a dog park during a pandemic). Or at least pick times when it will work better. The absolute worst situation IMO is where you dog is on a leash. They have no place to go and its very unnatural. Plenty of dogs growl when on a leash and then relax when taken off. Having two dogs on leashes "meet and greet" is always problematic.
Neutering will not change anything. Associating intact males to more aggressive behavior is a modern version of voodoo. The fact another male is also intact is likely irrelevant. The fact the other dog is male may not be.
Telling him "No" is also not likely to prove effective. Try distracting him with a yummy treat.
Majority of dog parks do not allow dogs into the park unless they are neutered or spayed. Especially males that are not neutered will act just like yours did, and if its the wrong type of dog......you got a full blown fight on your hands. Even though my 2 males are neutered, they do not like male dogs that are not "fixed".
A fight between your dog and another, one or the other, or maybe even both will get severely injured. It will not matter what or whose dog started the fight, another dog gets hurt by your dog YOU will have that dogs owner all over you! You will pay for vet bills and follow up bills and such. If you don't pay, she will take you to court. Like Pat and a few other's have said; do not take your dog to the dog park anymore. You need to seriously think about getting him neutered. If you continue to go and you see your dog start to growl or do something more serious, take him the heck out of the park before all hell breaks loose. You don't want your dog injured, and you don't want another dog to be injured by your dog.
Its the Basenji rutting season ! That time of year when they know the very future existence of the whole Basenji breed depends on THEM.
Neutering will not help - but he will settle down again after the seasonal hormonal surge. In fact it may well be a long time afterwards before he ceases to become restless around September / October. As I have often said, you can cut off the how to, but you can't excise the primordial urges.
Forget all thoughts of castrating and go to my website and read my article on The Rutting Season.
http://www.zandebasenjis.com/rutting.htm
In fact it might be a good time to suggest that all owners of young Basenji males have a read of that piece.
I respect everyone who has commented but I have to disagree on a few certain points. Please do not wait and see if he grows out of it. He will not. Dog reactivity only ever gets worse, not better, without intervention. It’s important to eliminate this behavior asap or it will solidify into a damning habit that will be harder and harder to get rid of as time goes on.
(The exception to this is if it is rutting like Zande mentioned, but you can’t know for sure if that’s all it is)
If he’s attacking dogs at the dog park, then I second those that suggested to (unfortunately, I know) stay away from the dog park.
But leash reactivity is honestly one of the most common and most fixable issues that pet dogs have. I’m not sure what you’re walking him on, but if it’s a harness, I strongly suggest you look into a martingale or prong collar (and then, of course, do lots of homework on how to use these tools properly - there are tons of fantastic videos on YouTube, which is a great place to start). If you control the head you control the dog, and solid leash manners are going to be key in eliminating leash reactivity. Do not try to ‘redirect’ the dog with a treat if he starts to growl, vibrate, lunge, etc. because a) chances are he will be too aroused to even notice the food and b) if he does notice it, he will interpret the food as a reward for the bad behavior of growling, lunging etc. and the problem will escalate. This is, unfortunately, a huge misconception in the dog training world. Food in response to shitty behavior will always, always be interpreted by the dog as a reward for said behavior, not as a deterrent.
Of course treats will come into play when you’re doing leash work. Start with zero distractions in your driveway or another private area and reward him for heeling and keeping his focus on you. Once you’ve done tons of repetitions then start adding in distractions like other dogs. Again, don’t respond to any reactive behavior with treats, but do reward him for ignoring distractions and keeping his focus on you.
I would also strongly suggest investing in a muzzle. Safety is #1 priority for you, your dog and others, and no matter the reason for the behavior, muzzles create a safety net that will allow you peace of mind when out and about with your dog. Baskervilles are the most popular and allow for eating, drinking and panting. If you size it right, your dog will barely even notice it’s there.
Edit: Also, there’s nothing wrong with not neutering him yet. You’re really not supposed to fix dogs until they reach sexual maturity, and that usually comes between 1-2 years of age (For bitches it’s after their first heat). I mean, you can, of course! But you don’t have to feel pressured into it. Like others have said, chances are it won’t fix the problem anyway
@theresab said in Male basenji puppy attacking other male dogs:
But leash reactivity is honestly one of the most common and most fixable issues that pet dogs have. I’m not sure what you’re walking him on, but if it’s a harness, I strongly suggest you look into a martingale or prong collar (and then, of course, do lots of homework on how to use these tools properly - there are tons of fantastic videos on YouTube, which is a great place to start). If you control the head you control the dog, and solid leash manners are going to be key in eliminating leash reactivity. Do not try to ‘redirect’ the dog with a treat if he starts to growl, vibrate, lunge, etc. because a) chances are he will be too aroused to even notice the food and b) if he does notice it, he will interpret the food as a reward for the bad behavior of growling, lunging etc. and the problem will escalate. This is, unfortunately, a huge misconception in the dog training world. Food in response to shitty behavior will always, always be interpreted by the dog as a reward for said behavior, not as a deterrent.
I want to strongly agree with the collar advice. I see so many people walking dogs in harnesses these days, and although you can get away with it if the dog is small, it will be very difficult to control a large dog with one. Leash manners are the place to start, of course, but ultimately if the dog "loses it" and ignores you, without control of the head you will have a very hard time controlling the dog.
The other point I want to agree with and emphasize is the one about unintentionally rewarding the wrong behaviour. I will say if you ask the dog for an incompatible behaviour (one that he can't accomplish while pulling and growling) and he complies, then sure, you can reward him for obedience, but treats offered when he is actively being aggressive will only reinforce his aggression.
Mind you, we are dealing with Basenjis here, and they are smart enough to learn that the way to get a treat is to act aggressive, obey your ensuing command, and get their treat! That is why the often used "trade" strategy for getting something away from the dog that he has stolen can backfire. Basenjis will figure out that the way to get a desirable treat is to grab something forbidden.
Not just a normal collar and leash and purrleeeze not a prong collar. Use a Gentle Leader. You are in control and he will know it, but not be able to do anything about it.
I don't like the use of a harness. I agree you need to control the head and because of the way it goes on, and has the lead actually leading him from under his 'chin' while exerting pressure on the back of his head, it is an excellent trainer.
And stay away from dog parks, especially at this time of year
@basenjimom2 thank you for your advise, i will avoid the dog park park until he is neutered.i don’t want him or any dog getting hurt.
@zande thank you, I will definitely try the leader 
@eeeefarm you are right, I turned to google on how to “fix” his behaviour and that’s where I got the idea to dangle a infront of him, I thought it was odd but I tried... and it didn’t work, he just ate the treat without even giving me eye contact, this is why I turn to this forum, I wanted advise from this who are familiar with basenji’s, as they are different from other breeds. I really appreciate everyone’s advise, I definitely have some more homework to do
@lindenbaum thank you so much!
d.melo............YOU have to show your dog that you are the leader. Otherwise he's going to walk all over you. My Mr.T came to me as his owner's were transferred to Brazil for their job. They bought him as a puppy from a breeder in Arizona where they lived. Apparently this was the first dog they ever had, or else they had NO clue about a Basenji. They never touched his feet, never picked him up.............nothing. He walked all over them. I didn't know that when he came to live with me..........which I found out real quick...............and he found out real quick that I was not going to tolerate his behavior. He hates getting shots, having his temp taken, blood drawn. He will BITE! That includes clipping his nails. Now I have to have a muzzle when he goes to the vet. He's fine getting weighed, but after that, the muzzle goes on. After all is done, muzzle come's off, and the vet and tech assistant both give him a treat so he knows that he gets good things afterwards. I also like and use Gentle Leaders for my dogs. I would walk all 3 (my Jenna crossed at age 17), so now its just the 2 boys with a gentle leader and one leash (coupler). Otherwise they would pull me. NOT a Haltie..............but a Gentle Leader.
The idea that you have to be the pack leader and assert yourself the right way to correct unwanted behavior is, unfortunately, a myth. The dominance method is not based in science and is the incorrect way to view dog behavior. The reasons that dogs do what they do have much simpler explanations than that they are testing you or trying to pull a fast one on you. This is why I urge you to seek out a trainer who is credentialed. Prong collars can increase aggression and solidify negative associations with other dogs. If you go Googling or YouTubing, make sure you first look at the source of the video or article. Is it from a trainer? If so, what are their credentials? (Google to find out.) What basis do they have for giving their advice?
Patricia McConnell and Karen Pryor are reputable sources: https://www.patriciamcconnell.com/
https://www.clickertraining.com/
Victoria Stillwell is also good: https://positively.com/
@lindenbaum said in Male basenji puppy attacking other male dogs:
The idea that you have to be the pack leader and assert yourself the right way to correct unwanted behavior is, unfortunately, a myth.
People have different ways of expressing the relationship between dog and owner. Lots of room for misinterpretation. The bottom line is that in a healthy relationship your dog respects you, sees you as the source of good things (like food, walks, etc.), and doesn't challenge your authority, for example by refusing to get off the couch! There is a lot to learn from various training approaches, and it's often true that "the only thing two trainers can agree on is that the third one is doing it wrong". Doing it "right" will be obvious by the results you get. You can take advice and try different things, but in dog training as in life the definition of insanity is doing the same thing over and over and expecting different results.
Operant conditioning works well, but it is important to understand the way positive and negative reinforcements work so that you can apply the appropriate one with the right timing to obtain the result you desire. But, you know what? People have been training dogs "unscientifically" for a very long time, and back in the day before all the buzz words and fanny packs of treats arrived, most ordinary folks managed to find ways to get their dogs to behave. 
"In order to get along with a Basenji, you have to be at least half as smart as the dog!"
@eeeefarm said in Male basenji puppy attacking other male dogs:
The bottom line is that in a healthy relationship your dog respects you, sees you as the source of good things (like food, walks, etc.), and doesn't challenge your authority,
In other words, you are his pack leader !
I've successfully lived this 'myth' since 1981 with a pack varying in size from 1 to 8 and every number in between.
Ditto to everything said by others. But also keep in mind, just because an owner says her dog is not in heat doens't mean her dog is not coming into heat. My Teddy can tell a bitch coming into heat a day or two before the human knows it. If there are intact dogs at your dog park, stop going there (I don't recommend dog parks either).
People who are saying to avoid dog parks this time of year, is that for all Basenjis across the globe? Are they known to be particularly naughty this time? We've actually noticed a couple of behavioral issues at the dog park, nothing too bad, but our boy is starting to act like he owns the park and his recall is shocking...thankfully he doesn't go far, he just doesn't care much about what we have to say either all he wants to do is play with other dogs.
@lokishadjie There are people on both sides of the dog park "fence". Some like it, some don't. I'm on the "like it" side. Primarily because it's obvious to me that my girl enjoys playing and interacting with the other dogs.
Generally speaking, the dog park can be fun for the dogs. There are occasional squabbles. Sometimes an owner is not as attentive as other owners would like them to be. Or there is a difference of (human) opinion on training. Life happens. My favorite dog park is mostly: the dogs play, the people chat, and everybody picks up after their pet(s). Doodle even likes to go when it's empty. She has no problem sunbathing, undisturbed, for an hour. IMHO, going to the dog park occasionally is a good thing. Going too often can create a spacial ownership ("It's my yard, I'm in charge here.") problem.
But! It's pretty much a guarantee that a new, or clueless, dog owner is going to show up at the dog park with their intact female who is "in season". That creates problems. The aroma lingers and once a male smells a female who is in season, all reason goes out the door. Males become aggressive. Typical male "survival" mode sets in. And they will fight each other over who is going to mate with her. Even after that particular female leaves... the scent remains and then the poor boys are so confused they will try to mate any girl around (even if that girl isn't "in season"). None of that makes for fun at the dog park.
I'm no Basenji expert since I've only had one. And, I don't want to start a dog park argument. I'll just share my experience.
Jengo LOVED running free, but he's a Basenji. Can't do that cause... cars. The dog park near our house is HUGE. A big completely enclosed lawn area the size of a football field with towering oak trees. We were OCD about keeping Jengo's vaccinations up to date. He was chipped and wore a collar with contact and rabies tags 24/7. He loved the dog park, but not all the dogs there. He hated any dog of any size that would try to dominate him in any way. He rarely instigated it, but he never tolerated it meaning regardless of size... he wouldn't back down. He also hated if another dog approached him from behind and would snap immediately.
My solution was to stay near him and to keep moving. We would walk laps around the perimeter and by about the second or third lap he'd been or had checked out all the other dogs. Then things were good. If I saw that he was getting anxious I'd usually catch it before he reacted and would tell him "Easy". 9 times out 10 that was enough. I'd also make sure that he was aware of dogs in our vicinity so that he wouldn't be surprised if they came from behind. We went to the park for years. He never caught anything that I was aware of. I did pick him up and leave if there was another dog he and/or I weren't comfortable with. And, I also recall walking away before ever entering the park if there was a dog we didn't like already there.
I guess my point is that part of protecting your dog and others is knowing and focusing on them without over-reacting at the same time. I don't want to set him off. But, I want to know what he's going to do before he does. You have to read him. All dogs give signals one way or another. Tune in to your dog, not the other people at the park. I liked the other people at the park, but I wasn't there for them. My focus was always on Jengo.
