i'm not sure if you're looking for specifically anti Vietnamese-American bias, but i too would be interested to hear of it, in part because of the low Vietnamese immigrant population in the united states during the war. vietnamese immigration was minor until saigon fell in 1975. So you'd expand your timeframe to include the postwar.
EDIT: u/keyilan has a good description of backlash after the war, which would probably a better question for OP to have asked.
Large-scale Vietnamese migration to the United States started as an influx of refugees following the end of the Vietnam War in 1975. Early refugees were part of a U.S.-sponsored evacuation and consisted mainly of military personnel and urban, well-educated professionals associated with the U.S. military or the South Vietnamese government.
In contrast, a second wave of Vietnamese refugees, commonly known as “boat people,” arrived in the late 1970s. The majority of these arrivals came from rural areas and were often less educated. Many of the Vietnamese refugees who arrived in the United States between 1983 and 2004 were initially resettled in states with large immigrant populations, including California, Texas, and Washington State—a fact largely reflected by the geographic distribution of Vietnamese immigrants today.
(excerpted from Lai & Arguelles, 1998, hosted at http://www.asian-nation.org/vietnamese.shtml)
EDit to add:
The most publicized anti-Vietnamese incident happened in Seadrift, TX where in 1979 a shrimpboater was killed by another Vietnamese shrimper. The Gulf Coast was an reasonable replacement for the Mekong Delta, and many vietnamese settled there, where they outcompeted the existing shrimpboaters, causing a lot of tension and violence. It was even made into a mediocre movie.
Further reading on Vietnamese shrimpers in the Gulf Coast & the death of Billy Joe Aplin here:
John Bloom, Texas Monthy 1979, "A Delicate Balance"
John Tedesco, San Antonio Express News 2000, "Leaving the past behind; Vietnamese shrimpers had another fight in Texas"
Andrew Chin, UNC Law School 2002, "The KKK and Vietnamese Fishermen"
However, when it comes to more general anti-Asian-American bias, there have been health-driven studies (bibliography at page's end) examining racial stressors contributing to PTSD, in which Vietnam veterans of Asian American/Pacific Islander heritage reported discrimination because they were identified with the enemy. These incidents might occur stateside or deployed in Vietnam. A Japanese-American soldier reported that:
he didn’t have problems with the men in his unit but often heard slurs from other enlisted Americans. When he was injured, military Medevac personnel assumed he was Vietnamese and nearly delayed his evacuation until all the solders they thought were American had been flown out.
“I got really upset, I started yelling back, ‘I’m an American. You get my ass out of here now,’” said the San Rafael, Calif., resident.
"I had to whip out my dog tag and say, "I'm an American,' " he said. "They'll get all the black and white guys before they get the Asians out."
In another incident, a Chinese-American Army nurse reported being mistaken for a Vietnamese prostitute.
The entirety of Chapter 2 of the linked book (another healthcare book; you can skim the methodology ¶s) by Zhan, 2003, Asian Americans: Vulnerable Populations, Model Interventions, and Clarifying Agendas has more stories from AAPI Vietnam vets, including being fired upon, assaulted, harassed, and stigmatized.
Edit: Just found this:
In boot camp in 1965, Escueta and his cousin Alex Fabros - the only two Asian Americans in the crowd of 200 - were chosen as "punching dummies" for hand-to-hand combat training. As Asian Americans, they had already become the butt of the drill instructor's anti-Viet Cong jokes and other racist comments. After two hours of pummeling by the DI, he ordered Escueta and Fabros to attack him once again. Escueta quickly turned the tables and slammed the DI to the ground. "As the instructor laid on the ground moaning in pain, Mel stood up, and in his best imitation of Charlie Chan's Chinese English, bowed to the crowd of astonished recruits and DIs and smiled," ... "Mel said: "That DI one damn good instructor; I not know this until he teach me today.' "
TLDR? Here's a short article.
There very much was, especially once refugees started coming in. I'm pasting here an older answer I gave to the same sort of question some time ago. This also gets to /u/HippopotamicLandMass' mention of the KKK, which was really a post-war thing, as was the shrimping conflicts.
During the aftermath of the Vietnam War there were a number of refugees who had been accepted by the US Government, but not without complaint from the general public. Most americans, at least those who were vocal about it at the time, were not so keen on the idea of allowing them into the country. In the 1975 most Americans surveyed were opposed, this according to a Gallup poll conducted at the time. Support for the plight of refugees during the war looked very different from support once the war was over.
Immediately following the end of the war, around 65,000 South Vietnamese were evacuated with help of the US (though with a considerable amount of corruption and extortion going on in the process). They were mostly evacuated to Thailand as a temporary stopover (a frequent temporary stopover for Southeast Asian refugees). In the end around 75,000 got to the US in that year
Much of what you’re probably seeing on the news today about Syrian refugees was also being said at the time about the Vietnamese refugees. They were criminals, corrupt, not the kind of people we want coming in, etc, that yes some were victims but many were just opportunists. Many in government expressed these opinions. As early as 1975 there were concerns that Vietnamese refugees would hurt an already suffering the domestic job market.
Not everyone was negative about the 1975 refugees, though. At the end of the war the Vietnamese government worked with the US to develop an agreement (called the Orderly Departure Program, ODP. See /u/Lich-Su's excellent clarification here) to allow South Vietnamese to leave unharmed, and the US had previously assured the Southerners of their support. In the end both things unravelled, with many feeling the US had abandoned the South, and by the 1980s the Vietnamese government was less willing to adhere to the ODP in light of US sanctions. Accepting the refugees, many felt, was required of the US to make good on their promises of support.
Despite mixed responses, from 1975 to 1978 when a much larger wave of refugees came, people talked about the risks and fears, but the refugees themselves faces a less fierce sort of opposition upon their arrival in the US, at least among the general public. There was opposition, but it only really picked up after the refugees became much more visible to the average working-class American.
The reasons for this opposition are nothing new. One of the biggest factors was the eternal myth of the un-assimiilable immigrant, the idea that Vietnamese coming into America would never really be fully American. This exactly echoes what Americans were saying 100 years before at the beginning of the period of Chinese Exclusion which officially ran from 1881-1943 but had waves much further back and forward. America has historically been upheld as a great melting pot, despite a well documented history of immigration policy and public opinion presenting a contrary position.
There was another significant factor in these attitudes as well, which again echoes the history of 100 years prior. In the 1970s the economy wasn’t in the greatest condition. People felt pressures of unemployment, and the growth of Japanese corporations as competition contributed to an already growing anti-Asian sentiment among nativists.
The state kept both of these issues in mind when the first group of immigrants came, and took steps to lessen the public outcry, but it didn’t really work, and there were a number of incidents over the coming years.
There were somewhat frequent minor scuffles (I’m not sure what to call them. Episodes of violence less that murder or hospitalisation). People were beaten up or their properly damages. Shops owned by Vietnamese were targeted, and often treated unfairly when not otherwise being harassed. It was especially problematic in Texas. Again, as in California a century earlier, the local white population felt growing resentment for the hard working Asian immigrants who were used to poorer conditions and who, due to significant differences in the structuring of social/kinship networks, were able to employ a much larger number of people, free of cost (being that they were family). People accused them of being communist because the "free labour" was seen as an indicator, never mind that many of these refugees were refugees in the first place because of their militant opposition to communism.
Shrimping was the main occupation of Vietnamese in Texas at this time, and in 1984 tensions between Vietnamese immigrants and the white population lead to the burning of multiple Vietnamese-own shrimping boats. This lead to fighting and one native-born American was killed.
However this was not the end of it. Soon the KKK was involved and began targeting Vietnamese families. Eventually this spread to places like New Orleans where a gunfight broke out, again among Vietnamese and local shrimpers.
The anti-Vietnamese sentiment had no trouble in being re-positioned as industry protectionism.
There were plenty of other instances of violence as well as well. In 1989 in central California a man shot up a playground with an AK-47 killing five children and injuring 29 more. Most of the victims Southeast Asian immigrants.
Then in places like LA there was anti-Korean sentiment, leading to the 1992 LA riots, and the Vietnamese were also lumped together with the Koreans* and were thus made targets, as they had been with the Japanese in the years before.
By the mid-1990s things had settled down more, but still, 20 years of conflict as refugees from decades of conflict back home is nothing to shake a stick at.
I want to add that not everyone in these communities faced the same degrees of violence, suspicion or negativity. There are a number of memoirs that speak more positively. The violence described above isn’t the only story. It’s just the one you asked about.
See also: